Sugar in soft drinks

At one time humans obtained most of their calories from food.  That changed with the arrival of cheap sugar, and then cheaper high-fructose corn syrup.

In the late 16th century, a teaspoon of sugar cost the equivalent of ten pounds in London (1).  Nowadays, 1 teaspoon of sugar costs approximately one pence (2).

 

Teaspoon of sugar

 

Sugar added to food now accounts for nearly 16 percent of the average American’s daily intake; sweetened soft drinks make up nearly half of that (3).

In Britain, government statistics indicate that 14.2 per cent of the calories in the average diet come from added sugars (4).

Researchers at Glasgow University asked 2,005 people from across the UK to estimate how many teaspoons of sugar were in some of the UK’s most popular drinks (5).  Those surveyed were also asked to estimate their average weekly liquid consumption in detail.

 

Sugar in soft drinks - estimated vs actual

 

The findings suggest that the average person in the UK consumes 659 grams of sugar and 3,144 calories per week (which equates to 450 calories per day) through non-alcoholic liquid intake.  This is the equivalent of nearly a quarter of recommended daily calories for a woman and a fifth for men.

People underestimated the amount of sugar in a serving of pomegranate juice by an average of 17.9 teaspoons, while they overestimated the amount of sugar in a serving of fruit squash by almost seven teaspoons.

It is worth noting that a number of products state they contain “100% juice” or “100% pomegranate juice”. You need to read the product label carefully because most products contain only 20 to 30 per cent pomegranate, with the rest typically apple or grape juice.

 

Pomegranate juice

Pomegranate juice

 

Professor Naveed Sattar said:

“While people sometimes overestimate the amount of sugar in carbonated drinks, they significantly underestimate the sugar levels in smoothies and fruit juices.

This analysis confirms that many people are perhaps not aware of the high calorie levels in many commonly consumed drinks.  Some varieties of drinks such as pure fruit juices and smoothies which are perceived as “healthy” options are also very high in sugar. For many people struggling with their weight, reducing their intake of such drinks and replacing with water or diet drinks would be a sensible first target to help them lessen their calorie intake.

For some, this change might seem difficult or impossible as they admit to having a “sweet tooth.”  However, it is now clear that our taste buds can be retrained over time to enjoy far less sugar in drinks (or no sugar at all).  But people deserve support and encouragement to make these changes and the soft drinks industry also has a role to play here by providing drinks with less sugar or offering cheaper diet versions.”

According to information from the British Soft Drinks Association, most soft drinks do not contain sugar.  Their data indicate that more than 60 per cent of the soft drinks market is now made up of diet, low calorie and no added sugar drinks, up from 30 per cent 20 years ago (6).

It is best to drink water but if you would like a fruit juice, here is a recipe for a watermelon, strawberry  and rose water crush, which is relatively low in sugars and calories.

 

Watermelon, strawberry and rose water crush

Watermelon, strawberry and rose water crush

 

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References


(3) Malik VS, Schulze MB, Hu FB.  Intake of sugar-sweetened beverages and weight gain: a systematic review. American Journal of Clinical Nutrition. 2006; 84:274-288

(4) DEFRA Food Statistics Pocket Book 2011

(6) British Soft Drinks Association 2011 UK Soft Drinks Report, data from Zenith International

How to lose weight

Many people resolve to go on a diet and adopt a healthier lifestyle, only to give up a few weeks later. Good intentions are often hard to put into practice and sustain. Here are a few suggestions to help you move towards and maintain a healthier weight:

1. Be realistic

Many people set themselves goals they find hard to achieve, such as fitting into a size 8 dress or a dinner jacket from 25 years ago. It is far better to begin by aiming to reduce your weight by 5 to 10 percent of your current weight. This may not turn you into a glamour model in a hurry, but it can lead to important improvements in weight-related conditions such as high blood pressure and diabetes. Once you have achieved this goal, you can always continue and aim to lose another 5 to 10 per cent until you are happy with your weight. Breaking the target down into manageable stages increases your chance of success.

2. Be gentle on yourself

Crash diets may work in the short-term but typically people regain all the weight they have lost and even add some more. Crash diets can also be dangerous. Not only this, but it is usually miserable being on a diet. Depriving yourself of food and feeling hungry sets up cravings which can lead to binge-eating followed by feelings of guilt. Neither deprivation nor hunger are necessary to lose weight if you are willing to take time and do the right things. If you cut out just 100 calories per day, the equivalent of a single can of fizzy drink or a bedtime snack, you could lose about 10 lb (4.5 kg) in a year. If you also added a brisk walk for half an hour a day five days per week, the weight loss could increase to 20 lb (9 Kg) in a year.

3. Keep moving

Next to not smoking, regular physical activity is arguably the best thing you can do for your health. It lowers the risk of heart disease, diabetes, stroke, high blood pressure, osteoporosis, and certain cancers, and can help to control stress and boost mood. Contrary to popular belief, the evidence for a simple relationship between physical activity and weight loss is equivocal, with some studies showing that exercise helps and others suggesting that it does not, possibly due to complex interactions between physical activity, diet and genes. If moderate to vigorous over an extended period, physical activity can help to maintain a healthy weight, provided you do not compensate by eating more as a self-reward. You would have to walk for 98 minutes to burn off the calories in one Mars Bar or swim for 45 minutes to burn off one slice of a pepperoni pizza, for example. For general health, any amount of exercise is better than none. The more you do, though, the better. This does not have to mean joining a gym or jogging. Many activities count as exercise: dancing, skating, gardening, cycling, scrubbing floors, washing the car by hand, or playing with children. Incorporate activity into your day by taking the stairs rather than the escalator, getting off the bus one stop before your destination and walking the rest, cycling to do errands rather than taking the car, and cutting back on watching television, playing computer games and other sedentary activities. Start slowly and gradually build up to more vigorous activity when your fitness increases.

4. Keep track

Many of us eat without thinking and have no idea how much we have consumed. Such lack of awareness can result in us eating and drinking more than we plan to. Try keeping a daily food diary for a while. List everything that you eat or drink, no matter how insignificant it seems. The calories can really add up, even just with drinks – one can of Coca Cola contains 142 calories, for example.

5. Eat food as nature intended

Research shows that people who eat at fast-food restaurants more than twice a week are more likely to gain weight and show early signs of diabetes than those who only occasionally eat fast food.

Our bodies were designed to consume food in the form that nature provides, with nothing added and nothing taken away.

Vegetables, fruit, nuts, seeds and whole grains all contain protein, carbohydrates, essential fats, vitamins, minerals and fibre. Fibre makes the food bulkier and less nutrient dense than highly processed food. This means that you have to eat a greater quantity of unprocessed food, like vegetables, to obtain the same amount of calories as highly processed foods, such as ice cream.

In the stomach and the gut, there are stretch receptors and nutrient receptors which signal to the body that it has enough food and to stop eating. If you eat highly processed foods, which are rich in calories but poor in vitamins, minerals and essential fats, such as white sugar and white bread, your body’s mechanism for signaling that it is full does not work properly – the gut is neither fully stretched nor receives the nutrients the body needs – so you carry on eating. This increases the chance of you consuming too many calories and becoming overweight, whilst not obtaining enough vitamins, minerals and essential fats.

The more unprocessed foods, like whole grains, vegetables, nuts and seeds, you include in your diet, the easier it is for your body to obtain the nutrients it needs without over-eating. Even if all you do is have porridge for breakfast instead of eating a sugary cereal or drinking strong coffee, you will find it easier to lose weight.

6. Keep your blood sugar stable

Another advantage of a food like porridge is that it has a gentle effect on blood sugar, or what’s called a low glycaemic index. When you eat porridge, glucose is released slowly and steadily into the bloodstream which helps to maintain energy levels over a longer period of time. This reduces hunger and cravings, so you tend to eat less. Other examples include whole grains such as brown rice (especially basmati), quinoa and whole-grain breads and pasta, as well as beans, nuts, fruits, and vegetables.

Eating foods that make your blood sugar and insulin levels shoot up and then crash may contribute to weight gain. Insulin tells the body to store surplus glucose as fat, so constantly excessive levels of glucose and insulin in the blood lead to weight gain. Such foods include white bread, white rice, and other highly processed grain products. So this is another good reason to increase the amount of unprocessed whole foods in your diet and reduce the amount of processed foods rich in calories.

7. Do not be afraid of good fats

Fat in a meal or in snacks such as nuts gives the food taste and helps you to feel full. Good fats, such as olive oil, have many benefits for health, including helping to improve your cholesterol levels when you eat them in place of saturated or trans fats or highly processed carbohydrates, like sugar and white flour products.

8. Drink water rather than fizzy drinks

Drinking juice or cans of sugary drinks can give you several hundred calories a day without even realising it. Several studies show that children and adults who consume sugar-sweetened beverages are more likely to gain weight than those who don’t, and that switching from these to water can reduce weight.

Using artificial sweeteners in soft drinks instead of sugar or high-fructose corn syrup seems like it would sidestep any problems with weight or diabetes. Artificial sweeteners deliver zero carbohydrates, fat, and protein, so they can’t directly influence calorie intake or blood sugar. Over the short term, switching from sugar-sweetened soft drinks to diet drinks cuts calories and leads to weight loss. Long-term use, though, may be a different story.

Some long-term studies show that regular consumption of artificially sweetened beverages reduces the intake of calories and promotes weight loss or maintenance. Others show no effect, while some show weight gain.

One concern about artificial sweeteners is that they uncouple sweetness and energy. Until recently, sweet taste meant sugar, and thus energy. Glucose is critical for the human brain to function, so the body has delicate feedback mechanisms involving the brain, stomach, nerves and hormones, to ensure that there is always a steady supply. When we eat something sweet, the human brain responds with signals – first with signals to eat more, and then with signals to slow down and stop eating. By providing a sweet taste without any calories, artificial sweeteners could confuse these intricate feedback loops. This could potentially throw off the body’s ability accurately to gauge how many calories are being taken in. Studies in rats support this idea. Researchers at Purdue University have shown that rats eating food sweetened with saccharin took in more calories and gained more weight than rats fed sugar-sweetened food. In addition, a long-term study of nearly 3,700 residents of San Antonio, Texas, showed that those who averaged three or more artificially sweetened beverages a day were more likely to have gained weight over an eight-year period than those who didn’t drink artificially sweetened beverages. At present, research findings are mixed, but there is a possibility that diet drinks may lead to weight gain in the longer term.

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References

Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults: the evidence report. National Institutes of Health, National Heart, Lung, and Blood Institute, Obesity Education Initiative

Haskell WL, Lee IM, Pate RR, et al. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc. 2007; 39:1423–34

Pronk NP, Wing RR. Physical activity and long-term maintenance of weight loss. Obes Res. 1994 Nov;2(6):587-99

Fogelhom M, Kukkonen-Harjula K. Does physical activity prevent weight gain – a systematic review Obesity Reviews, Volume 1, Issue 2, 95–111, October 2000

Pereira MA, Kartashov AI, Ebbeling CB, et al. Fast–food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis. Lancet. 2005; 365:36–42

Bellisle F, Drewnowski A. Intense sweeteners, energy intake and the control of body weight. European Journal of Clinical Nutrition. 2007; 61:691-700

Swithers SE, Davidson TL. A role for sweet taste: calorie predictive relations in energy regulation by rats. Behavioral Neuroscience. 2008; 122:161-173

Fowler SP, Williams K, Resendez RG, Hunt KJ, Hazuda HP, Stern MP. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity (Silver Spring). 2008; 16:1894-1900

Frank GK, Oberndorfer TA, Simmons AN, et al. Sucrose activates human taste pathways differently from artificial sweetener. Neuroimage. 2008; 39:1559-1569

Willett, W. Eat, drink and be healthy. Harvard Medical School Guide to Healthy Eating. The Free Press; Free Press Trade Pbk. Ed edition (April 2005). ISBN: 978-0743266420.

Lisle D, Goldhamer A. The Pleasure Trap – Mastering the Hidden Force that Undermines Health and Happiness.  Healthy Living Publications, 30 March 2006

Drinks may contribute more to obesity than food

drinksWhile the energy density of soft drinks, which are frequently highly calorific, needs to be considered differently from that of solid foods, recent research has demonstrated that consumption of soft drinks is likely to increase normal caloric intake.  When people consume soft drinks, they do not recognise that they have taken in extra energy and compensate by reducing energy from elsewhere in their daily diet, or by expending additional energy; they simply add it on. 

A standard 330 ml can of Coca-Cola contains 139 calories. Thus if a person were to consume a can of Coca-Cola with two meals per day, over a week that would result in an energy surplus of nearly 2,000 calories-more than a whole day’s recommended calorie intake for the average woman, and about  three-quarters of the recommended daily calorie intake for a man. Evidence from the British Soft Drinks Association suggests that children drink an average of 4.7 litres of soft drink per week, of which only 10% are fruit juice or water. 

Consumption of alcohol, particularly amongst women and young people in the UK, has increased dramatically during the past years. Since 1970, alcohol consumption in the UK has increased by 40 per cent. With most alcoholic drinks being at least as calorific as a high-sugar soft drink, such as Coca-Cola, it would seem intuitive that the massive increase in their consumption has had some impact on the nation’s weight. Much attention has focused in recent months on the growing culture of ‘binge drinking’, particularly amongst young people. While the health risks associated with this are well documented, what is less publicised is that drinking five pints of lager over an evening adds an extra 1,135 calories, nearly half a man’s daily energy requirement, and five bottles of an ‘alcopop’ such as Bacardi Breezer contain 990 calories, nearly half a woman’s daily energy requirement. 

Researchers from the Johns Hopkins Bloomberg School of Public Health examined the relationship between beverage consumption among adults and weight change and found that weight loss was positively associated with a reduction in liquid calorie consumption and liquid calorie intake had a stronger impact on weight than solid calorie intake. The results are published in the April 1, 2009, issue of the American Journal of Clinical Nutrition. 

“Both liquid and solid calories were associated with weight change, however, only a reduction in liquid calorie intake was shown to significantly affect weight loss during the 6-month follow up,” said Benjamin Caballero MD, PhD, senior author of the study and a professor with the Bloomberg School’s Department of International Health. “A reduction in liquid calorie intake was associated with a weight loss of 0.25 kg at 6 months and 0.24 kg at 18 months. Among sugar-sweetened beverages, a reduction of 1 serving was associated with a weight loss of 0.5 kg at 6 months and 0.7 kg at 18 months. Of the seven types of beverages examined, sugar-sweetened beverages were the only beverages significantly associated with weight change.”

Researchers conducted a prospective study of 810 adults aged 25-79 years old participating in the PREMIER trial, an 18-month randomized, controlled, behavioural intervention. Caballero along with colleagues from the Johns Hopkins School of Medicine; the National Heart, Lung, and Blood institute; Duke University; the Pennington Biomedical Research Center; the Kaiser Permanente Center for Health Research; the University of Alabama; and Pennsylvania State University measured participant’s weight and height using a calibrated scale and a wall-mounted stadiometer at both 6 and 18 months. Dietary intake was measured by conducting unannounced 24-hour dietary recall interviews by telephone. 

Researchers divided beverages into several categories based on calorie content and nutritional composition: 

  • sugar-sweetened beverages (regular soft drinks, fruit drinks, fruit punch, or high-calorie beverages sweetened with sugar)
  • diet drinks (diet soda and other “diet” drinks sweetened with artificial sweeteners)
  • milk (whole milk, 2 percent reduced-fat milk, 1 percent low-fat milk, and skim milk)
  • 100 percent juice (100 percent fruit and vegetable juice)
  • coffee and tea with sugar, coffee and tea without sugar and
  • alcoholic beverages.

They found that at 37 percent sugar-sweetened beverages were the leading source of liquid calories. 

Consumption of liquid calories from beverages has increased in parallel with the obesity epidemic.

Earlier studies by Bloomberg School researchers project that 75 percent of U.S. adults could be overweight or obese by 2015 and have linked the consumption of sugar-sweetened beverages to the obesity epidemic, which affects two-thirds of adults and increases the risk for adverse health conditions such as type 2 diabetes. 

Researchers recommend limited liquid calorie intake among adults and to reduce sugar-sweetened beverage consumption as a means to accomplish weight loss or avoid excess weight gain. 

“Among beverages, sugar-sweetened beverages was the only beverage type significantly associated with weight change at both the 6- and 18-month follow up periods,” said Liwei Chen, MD, PhD, MHS, lead author of the study and a Bloomberg School graduate. “Changes in the consumption of diet drinks and alcoholic beverages were inversely associated with weight loss, but were not statistically significant. Our study supports policy recommendations and public health efforts to reduce intakes of liquid calories, particularly from sugar-sweetened beverages, in the general population.” 

In the UK, little government attention seems to be given to the impact of soft drink and alcohol consumption on obesity.  The adverse health effects of excess alcohol consumption are well-documented but its effects on weight gain are underestimated. The effect of alcohol on obesity is not even mentioned in the Chief Medical Officer’s recent Annual Public Health Report, which created controversy by suggesting a range of measures to address the nation’s drink problem. 

“Easy access to cheap alcohol is “killing us as never before” and must be curbed with tough licensing laws, price rises and a shift in public opinion that makes being drunk as unacceptable as smoking”.  

Responding to comments from Downing Street that the majority of sensible drinkers should not have to pay for the excessive drinking of the minority, Sir Liam said: “I take a different view as to whether heavy drinking is a minor and insignificant problem.” 

If the UK government is not yet prepared to tackle the well-understood health problems associated with alcohol consumption, we clearly have a long way to go before its effect on obesity reaches the radar screen. 

For information on the effects of different types of drinks on health and creative ideas for healthy drinks, please come to a Cooking for Health course, held throughout the year in Somerset, UK, led by nutrition expert Dr Jane Philpott.

Obesity reduces life expectancy by 3 to 10 years

A new analysis of almost one million people from around the world has shown that obesity can trim years off life expectancy.

The Oxford University research found that moderate obesity, which is now common, reduces life expectancy by about 3 years, and that severe obesity, which is still uncommon, can shorten a person’s life by 10 years. This 10 year loss is equal to the effects of lifelong smoking. 

obesity2331

The analysis brought together data from 57 long-term research studies mostly based in Europe or North America. People were followed for an average of 10 to 15 years, during which 100,000 died, making it the largest ever investigation of how obesity affects mortality. It was coordinated by the Clinical Trial Service Unit (CTSU) in Oxford and the results are published online (28 March) in The Lancet

The studies used body mass index (BMI) to assess obesity. BMI is calculated by dividing a person’s weight in kilograms (kg) by the square of their height in metres (m). If a person has a BMI of 30 to 35, then they are moderately obese; if they have a BMI of 40 to 50, they are severely obese. Though not perfect, BMI is useful for assessing the extent to which fatty tissue causes ill health. 

obese-woman-460x276

Among the 900,000 men and women in the study, mortality was lowest in those who had a BMI of 23 to 24. This means that if a person were 1.70m (5 feet 7 inches) tall, for example, his or her optimum weight would be about 70kg (154 pounds or 11 stone). 

This study has shown that continuing to smoke is as dangerous as doubling your body weight, and three times as dangerous as moderate obesity.

Epidemiologist Dr Gary Whitlock of Oxford University, who led the analysis, said of the findings:

”Excess weight shortens human lifespan. In countries like Britain and America, weighing a third more than the optimum shortens lifespan by about 3 years. For most people, a third more than the optimum means carrying 20 to 30 kilograms [50 to 60 pounds, or 4 stone] of excess weight. If you are becoming overweight or obese, avoiding further weight gain could well add years to your life.”

Comparing the effects of obesity with those of smoking, the study’s main statistician, Oxford University Professor Sir Richard Peto, said:

“This study has shown that continuing to smoke is as dangerous as doubling your body weight, and three times as dangerous as moderate obesity. Changing your diet but keeping on smoking is not the way to increase lifespan. For smokers the key thing is that stopping smoking works.” 

In those who were moderately obese (BMI 30 to 35, which is now common), the lifespan was reduced by three years. Severe obesity (BMI 40 to 50, which is still uncommon) reduced life expectancy by about 10 years; this is similar to the effect of lifelong smoking. Although severe obesity is more common in North America than in Europe, in both places it is much less common than moderate obesity, which has only a third of the effect on lifespan that smoking does.  

There was also a higher death rate among those who had a BMI well below 23 to 24, mainly because of strong inverse associations with respiratory disease and lung cancer. This hazard was much greater for smokers than for non-smokers.

Obesity increases death rates for some types of cancer, but the main way it kills is by increasing risk of heart disease and stroke. Amongst middle-aged people in the UK, as many as one in four deaths from heart attack or stroke and one in 16 cancer deaths are due to being overweight or obese. In the US, where middle-aged people are typically a few kilograms heavier, the figures are even higher: one in three heart attack or stroke deaths and one in 12 cancer deaths in the US are due to being overweight or obese.

Have you spent years embarking on every weight-loss diet going? Have you tried cutting out entire food groups? Have you spent a fortune on miracle foods or diet powders? Have you eaten nothing except cabbage soup for weeks? Have you driven your friends mad with your fervour over food combining? Have you become obsessive about counting calories or points? Have you spent hours jumping on and off your bathroom scales? Do you feel hungry much of the time, exhausted and beset by cravings?

Our bodies evolved over millions of years to work perfectly with a diet of naturally available unprocessed foods. Our ancestors were not fat because they ate this optimum diet and exercised every day. Today, some societies in the world maintain this traditional type of diet and remain lean and at low risk of diabetes, heart disease, cancer and dementia.

You can learn how to lose weight effortlessly without feeling hungry, whilst gaining health and vitality, at a Cooking for Health class on “Managing Your Weight Naturally“. We explore why so many diets fail and explode many of the weight loss myths. We look at cravings – how they arise and how to overcome them – and we discuss which foods the body needs to create energy and burn fat in the most efficient way. We create a delicious meal with an array of different dishes designed to illustrate how it is possible to eat plenty without gaining weight.

Weight loss diets – a new study asks which are the best?

Many popular diets emphasize either carbohydrate, protein or fat as the best way to lose weight.

paleo-diet2Advocates of high protein diets claim that our Paleolithic ancestors obtained the majority of their calories from meat and thus our bodies have evolved to require a high protein intake.  There is much scientific controversy over the relative importance of animal and plant foods in the early hominid diet.  Direct evidence in the form of food remains is meagre or, at best, equivocal.  Most research relies on inference through dietary studies of other primates and archaeological evidence.  Most scientists now agree that plant foods contributed much more to the early hominid diet than did the flesh of animals. 

okinawa_diet_planHumans have adapted to their environments wherever they have settled and the balance between meat-eating and plant-eating varies substantially between populations.  Some of the leanest and healthiest societies in the world, such as in the Mediterranean and Japan, consume a diet where the majority of energy comes from carbohydrates, mainly in the form of complex carbohydrates from whole grains and vegetables.  This has led some researchers to propose that a high carbohydrate diet is better for maintenance of a healthy weight than a high protein diet.

Controversy about the role of fat in the diet has raged since the 1950s, when Ancel Keys published his landmark “Seven Countries” study and highlighted that coronary heart disease is strongly related to diet.  Low-fat diets have therefore been promoted by governments and health professionals for several decades.

With the prevalence of obesity increasing at an alarming rate, everyone wants to know which of these dietary approaches – high protein, high carbohydrate, low fat – is the most successful for weight loss.

obese-women

The scientific research conducted to date does not help much.  Some trials have shown that low-carbohydrate, high-protein diets resulted in more weight loss over the course of 3 to 6 months than conventional high-carbohydrate, low-fat diets, but other trials have not shown this effect.

A smaller group of studies that extended the follow-up to 1 year did not show that low-carbohydrate, high-protein diets were superior to high-carbohydrate, low-fat diets.  In contrast, other researchers found that a very-high-carbohydrate, very-low-fat vegetarian diet was superior to a conventional high-carbohydrate, low-fat diet.  Among the few studies that extended beyond 1 year, one showed that a very-low-fat vegetarian diet was superior to a conventional low-fat diet, one showed that a low-fat diet was superior to a moderate-fat diet, two showed that a moderate-fat, Mediterranean-style diet was superior to a low-fat diet, one showed that a low-carbohydrate diet was superior to a low-fat diet, and another showed no difference between high-protein and low-protein diets.

Small samples, underrepresentation of men, limited generalizability, a lack of blinded ascertainment of the outcome, a lack of data on adherence to assigned diets, and a large loss to follow-up limit the interpretation of many weight-loss trials.  The novelty of the diet, media attention, and the enthusiasm of the researchers may affect the adherence of participants to any type of diet.

There have been few studies lasting more than a year that evaluate the effect on weight loss of diets with different compositions of those nutrients. In a randomized clinical trial led by researchers at the Harvard School of Public Health (HSPH) and Pennington Biomedical Research Center of the Louisiana State University System, a comparison of overweight participants assigned to four different diets over a two-year period showed that reducing calories achieved weight loss regardless of which of the three nutrients was emphasized. The study, which was funded by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health, appears in the February 26, 2009 issue of The New England Journal of Medicine.

“This is important information for physicians, dieticians and adults, who should focus weight loss approaches on reducing calorie intake,” said Frank Sacks, professor of cardiovascular disease prevention at HSPH and lead author of the study.

The trial included 811 men and women who were randomly divided into four diet groups with different target nutrient compositions:

  • Low-fat, average protein: 20% of calories from fat, 15% of calories from protein, 65% of calories from carbohydrate
  • Low-fat, high-protein: 20% fat, 25% protein, 55% carbohydrate
  • High-fat, average protein: 40% fat, 15% protein, 45% carbohydrate
  • High-fat, high-protein: 40% fat, 25% protein, 35% carbohydrate

The participants were diverse in age, sex (62% women, 38% men), geography and income. The diets followed heart-healthy principles, replacing saturated with unsaturated fat and were high in whole cereal grains, fruits and vegetables. Each participant received a diet prescription that encouraged a 750-calorie reduction per day, however none were less than 1,200 total calories per day. Participants were asked to do 90 minutes of moderate exercise each week. They recorded their daily food and drink intake in a food diary and in a web-based program that provided information on how closely they were meeting their dieting goals. Individual counselling was provided every eight weeks over two years and group sessions were held three out of four weeks during the first six months and two out of four weeks from six months to two years.

The results showed that, regardless of diet, weight loss and reduction in waist circumference were similar. Participants lost an average of 13 pounds at six months and maintained a 9-pound loss at two years. Weight loss primarily took place in the first 6 months; after 12 months, all groups began to slowly regain weight, a finding consistent with other diet studies. However, the extent of weight regain was much less, about 20%, of the average regain in previous studies. Waistlines were reduced by an average of two inches at the end of the two-year period.

Most risk factors for cardiovascular disease improved for dieters at six months and two years. HDL (“good”) cholesterol increased and LDL (“bad”) cholesterol, triglycerides, blood pressure and insulin decreased. The metabolic syndrome, a group of coronary heart disease risk factors including high blood pressure, insulin resistance and abdominal obesity, also decreased.

The main finding from the trial was that diets with varying emphases on carbohydrate, fat and protein levels all achieved clinically meaningful weight loss and maintenance of weight loss over a two-year period.

“These results show that, as long as people follow a heart-healthy, reduced-calorie diet, there is more than one nutritional approach to achieving and maintaining a healthy weight,” said Elizabeth G. Nabel, M.D., Director, NHLBI.

Another important finding was that participants who regularly attended counselling sessions lost more weight than those who didn’t. Dieters who attended two thirds of sessions over two years lost about 22 pounds of weight as compared to the average weight loss of 9 pounds.

“These findings suggest that continued contact with participants to help them achieve their goals may be more important than the macronutrient composition of their diets,” said Sacks.

fruit_and_veg11

Have you spent years embarking on every weight-loss diet going?  Have you tried cutting out entire food groups?  Have you spent a fortune on miracle foods or diet powders?  Have you eaten nothing except cabbage soup for weeks?  Have you driven your friends mad with your fervour over food combining?  Have you become obsessive about counting calories or points?  Have you spent hours jumping on and off your bathroom scales?  Do you feel hungry much of the time, exhausted and beset by cravings?

You can learn how to lose weight effortlessly without feeling hungry, whilst gaining health and vitality, at a Cooking for Health course on Managing Your Weight Naturally.  We explore why so many diets fail and explode many of the weight loss myths.  We look at cravings – how they arise and how to overcome them – and we discuss which foods the body needs to create energy and burn fat in the most efficient way.  We create a delicious meal with an array of different dishes designed to illustrate how it is possible to eat plenty without gaining weight.  The vital role of exercise in maintaining a healthy weight is also emphasised.

References

Strassman, B.I. and Dunbar, R.I. (1999).  Human evolution and disease: putting the Stone Age in perspective.  In Stearns, S.C. ed Evolution in Health and Disease, Oxford: Oxford University Press.

Lee, R.B.  The !Kung San: Men, Women and Work in a Foraging Society.  Cambridge University Press, 1979

Lee, R.B. & Devore, I.  Man the Hunter. Aldine De Gruyter (December 31, 1999)

Jéquier E, Bray GA. Low-fat diets are preferred. Am J Med 2002;113:Suppl:41S-46S

Willett WC, Leibel RL. Dietary fat is not a major determinant of body fat. Am J Med 2002;113:Suppl:47S-59S

Freedman MR, King J, Kennedy E. Popular diets: a scientific review. Obes Res 2001;9:Suppl:1S-40S

Skov AR, Toubro S, Rønn B, Holm L, Astrup A. Randomized trial of protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity. Int J Obes Relat Metab Disord 1999;23:528-536.

Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. J Clin Endocrinol Metab 2003;88:1617-1623.

Foster GD, Wyatt HR, Hill JO, et al. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med 2003;348:2082-2090.

Samaha FF, Iqbal N, Seshadri P, et al. A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med 2003;348:2074-2081.

Yancy WS Jr, Olsen MK, Guyton JR, Bakst RP, Westman EC. A low-carbohydrate ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Ann Intern Med 2004;140:769-777.

Volek J, Sharman M, Gómez A, et al. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutr Metab (Lond) 2004;1:13-13.

Due A, Toubro S, Skov AR, Astrup A. Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial. Int J Obes Relat Metab Disord 2004;28:1283-1290.

Gardner CD, Kiazand A, Alhassan S, et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A to Z Weight Loss Study: a randomized trial. JAMA 2007;297:969-977. [Erratum, JAMA 2007;298:178.]

Shai I, Schwarzfuchs D, Henkin Y, et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008;359:229-241.

Noakes M, Keough JB, Foster PR, Clifton PM. Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional low-fat, high-carbohydrate diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am J Clin Nutr 2005;81:1298-1306.

McLaughlin T, Carter S, Lamendola C, et al. Effects of moderate variations in macronutrient composition on weight loss and reduction in cardiovascular disease risk in obese, insulin-resistant adults. Am J Clin Nutr 2006;84:813-821.

McMillan-Price J, Petocz P, Atkinson F, et al. Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults: a randomized controlled trial. Arch Intern Med 2006;166:1466-1475.

Das SK, Gilhooly CH, Golden JK, et al. Long-term effects of 2 energy-restricted diets differing in glycemic load on dietary adherence, body composition, and metabolism in CALERIE: a 1-y randomized controlled trial. Am J Clin Nutr 2007;85:1023-1030.

Lecheminant JD, Gibson CA, Sullivan DK, et al. Comparison of a low carbohydrate and low fat diet for weight maintenance in overweight or obese adults enrolled in a clinical weight management program. Nutr J 2007;6:36-36.

Foster GD, Wyatt HR, Hill JO, et al. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med 2003;348:2082-2090

Due A, Toubro S, Skov AR, Astrup A. Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial. Int J Obes Relat Metab Disord 2004;28:1283-1290

Stern L, Iqbal N, Seshadri P, et al. The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial. Ann Intern Med 2004;140:778-785.

Dansinger ML, Gleason JA, Griffith JL, Selker JP, Schaefer EJ. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. JAMA 2005;293:43-53.

Luscombe-Marsh ND, Noakes M, Wittert GA, Keough JB, Foster P, Clifton PM. Carbohydrate restricted diets high in either monounsaturated fat or protein are equally effective in promoting fat loss and improving blood lipids. Am J Clin Nutr 2005;81:762-772.

Keogh JB, Luscombe-Marsh ND, Noakes M, Wittert GA, Clifton PM. Long-term weight maintenance and cardiovascular risk factors are not different following weight loss on carbohydrate-restricted diets high in either monounsaturated fat or protein in obese hyperinsulinemic men and women. Br J Nutr 2007;97:405-410.

Ornish D, Scherwitz LW, Billings JH, et al. Intensive lifestyle changes for reversal of coronary heart disease. JAMA 1998;280:2001-2007. [Erratum, JAMA 1999;281:1380.]

Barnard ND, Cohen J, Jenkins DJ, et al. A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care 2006;29:1777-1783.

Turner-McGrievy GM, Barnard ND, Scialli AR. A two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat diet. Obesity (Silver Spring) 2007;15:2276-2281. 

Toubro S, Astrup A. Randomized comparison of diets for maintaining obese subjects’ weight after major weight loss: ad lib, low fat, high carbohydrate diet v fixed energy intake. BMJ 1997;314:29-34

Shai I, Schwarzfuchs D, Henkin Y, et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008;359:229-241

McManus K, Antinoro L, Sacks F. A randomized controlled trial of a moderate-fat, low-energy diet compared with a low fat, low-energy diet for weight loss in overweight adults. Int J Obes Relat Metab Disord 2001;25:1503-1511

Due A, Toubro S, Skov AR, Astrup A. Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial. Int J Obes Relat Metab Disord 2004;28:1283-1290

Simons-Morton DG, Obarzanek E, Cutler JA. Obesity research — limitations of methods, measurements, and medications. JAMA 2006;295:826-828.