POPULAR DIETS

Part Two: High Carbohydrate Diets

A lot of publicity has been given to a wide variety of diets lately. Some of these advocate high protein intake, some stress carbohydrate, others make no reference to carbohydrate or protein. What are these diets supposed to achieve, and what, if any, is the scientific evidence supporting them?

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.

"The diets reviewed here are 'Eat More Weigh Less' (Dr Dean Ornish), 'The McDougall Program for Maximum Weight Loss' (Dr John McDougall), the 'Pritikin' Diet (Dr Robert Pritikin), 'Eight Weeks to Optimum Health' (Dr Andrew Weil), and the 'GutBusters' program (Dr Garry Egger and Dr Rosemary Stanton)."

In summary, all these diets are believed to be essentially health- promoting and are likely to lead to loss of body fat in the medium to long term. Furthermore, there is good evidence that the combinations of diets and lifestyles  advocated by Dr Ornish and Robert Pritikin can be effective in preventing (and even reversing) atherosclerosis (the 'hardening of the arteries' that can eventually lead to a heart attack).

The major problem likely to be associated with attempting to adopt the diet of Dr Ornish or Robert Pritikin is that these diets represent a huge change from the typical Western diet. The massive reduction in fat intake recommended by these authors (relative to usual fat intakes in Australia) probably means that these diets will be maintained only by people with good reason to do so (such as those who already have heart disease or diabetes) or who have extremely strong will power.

Please note that anyone who does already have heart disease or diabetes (or other medical condition that might be diet-related) should consult their doctor or dietitian about appropriate alterations in diet and lifestyle, and always take their advice rather than the advice offered here (or elsewhere).

Dr McDougall's diet is also basically sound, but he inappropriately recommends eliminating bread during the early stages of weight reduction, and his recommended rate of weight loss is excessive. He also believes (incorrectly) that milk cannot be digested by most adults in Western countries. His recommended very high level of carbohydrate intake (and low fat intake) also mean that compliance with this diet may be difficult for many people.

Dr Weil's program is essentially orthodox, but he does advocate the almost exclusive use of olive oil over edible oils. Although there is good evidence that olive oil may be particularly health-promoting among the edible oils, it may inappropriate (or at least premature) to advocate using only olive oil. Mono- and polyunsaturated margarines and cooking oils and salad dressings (when used sparingly) are also believed to be health-promoting. 

The GutBusters program has been shown to be effective in achieving some reduction in dietary fat intake and alcohol consumption, and a slight reduction in waist size in Australian men. This program is worthy of consideration by men (and women) who are serious about reducing their level of 'abdominal adiposity' (more commonly known in Australia as a 'beer gut' when it occurs on men).

Finally, diet is only one lifestyle factor that needs to be considered in trying to optimise health outcome. Physical activity is equally important. The recommended lifestyle for optimal health and wellness includes a diet based on a wide variety of nutritious foods (with the greatest emphasis on foods of plant origin), and at least 30 minutes per day of moderately vigorous activity.

HIGH CARBOHYDRATE DIETS

Over the past several years many diets have been recommended to the public, often with promises of improved health, greater life expectancy, and/or weight loss resulting from adoption of each particular diet. Most of these diets can be assigned to the 'high protein' or 'high carbohydrate' category, although some don't fit neatly into either category.

The first point that needs to be made is that the term 'diet' doesn't have the meaning it may have had a few years ago -- that is, a short-term change in eating patterns to attain a specific goal (such as losing weight). Now, the proponent of a diet is usually advocating an eating plan for a lifetime, not a short-term means of overcoming a perceived problem (such as being overweight).

In this answer (Popular Diets: Part 2), some popular high carbohydrate diets are reviewed, with several high protein diets and 'in between' diets being discussed in separate answers in this series of FAQs [see 'Popular Diets: Part 1' and 'Popular Diets: Part 3', respectively].

Among the most popular high carbohydrate diets are 'Eat More Weigh Less' (Dr Dean Ornish), 'Eight Weeks to Optimum Health' (Dr Andrew Weil), 'The McDougall Program for Maximum Weight Loss' (Dr John McDougall), the 'Pritikin' diet (Dr Robert Pritikin) and 'GutBusters' (Dr Garry Egger and Dr Rosemary Stanton).

Although all these diets advocate increased carbohydrate intake compared to the current typical Australian diet, they are not all identical in other significant ways and so are addressed separately below (in no particular order).

EAT MORE WEIGH LESS (Dr Dean Ornish)
This diet is one of two that have the same name (confusing, isn't it!). Both Dr Ornish and Dr Terry Shintani have chosen this name for their diet, but only the Ornish diet is reviewed here. It is available as a book ('Eat More Weigh Less') and some additional information is available at http://www.fatfree.com/diets/ornish.html.

The name of this diet is based on the concept that if you eat a very high starch/high fibre diet, you can actually eat a greater total weight of food than usual, and still lose body fat. As a result the diet advocates extremely high carbohydrate intake. Following Dr Ornish's advice will lead to approximately the same level of protein consumption as the typical current Western diet, but only about one-third the usual quantity of fat.

The original point of the diet was to try to halt (and even reverse) the process of atherosclerosis (the 'hardening of the arteries' that can eventually trigger heart attacks). Dr Ornish recommends high consumption of 'complex carbohydrates' -- whole grain breads and cereals, fruits and vegetables -- rather than of simple sugars. This makes the diet very high in volume and fibre (and therefore 'filling') even though total kilojoule intake is relatively low.

Such a diet will very likely induce weight loss, because it has a 'low energy density'; that is, you would have to eat a huge quantity of such foods before your kilojoule requirement could be exceeded. Therefore, putting on weight, or even maintaining a high body weight, would be very difficult on this diet.

Although this is not a totally vegetarian ('vegan') diet, Dr Ornish does not include meat (red or white), eggs or fish in his list of recommended foods, and suggests that only low-fat dairy food be consumed. His advice about dairy foods is orthodox, but completely avoiding meat and fish ignores the contribution that these foods can make to intakes of essential minerals such as niacin, iron and magnesium (meat), and the important 'omega-3' fatty acids (fish).

Dr Ornish recognises that there is more to good health and controlling our weight than simply eating a particular diet. He also suggests networking with others who have adopted his diet and providing mutual encouragement. Relaxation and physical activity are also regarded as important. Finally, light alcohol consumption is tolerated. All these are sensible recommendations and are compatible with current, orthodox nutrition knowledge.

Dr Ornish has published peer-reviewed papers in prestigious medical journals indicating that adherence to his diet, combined with stress reduction and exercise, may be effective in halting the progress of atherosclerosis in heart disease patients, and in treating diabetes. His results even suggest that some of the damage to the heart's arteries can be undone (that is, reversal of atherosclerosis has been observed).

However, much time is taken up in preparing the types of meals he recommends. With today's busy lifestyles, and with most Western people used to high fat intakes, this diet is probably suitable only for people who already have atherosclerosis or diabetes (and then only when recommended by their doctor or dietitian) or who have very strong will power and are extremely keen to lose weight or to improve their nutritional status generally.

Summary
The Dr Ornish 'Eat More Weigh Less' diet is a nutritious and health-promoting diet, although it places inappropriate limits on consumption of meat and dairy products. This diet would very likely achieve the aims of reducing weight and reducing the risk of heart disease in the vast majority of people, but its extreme nature makes long-term compliance unlikely for all but the most strongly motivated. 

THE MCDOUGALL PROGRAM FOR MAXIMUM WEIGHT LOSS
This is the title of a book by Dr John McDougall. Other books he has written include 'The McDougall Program for a Healthy Heart', 'The McDougall Program: 12 Days to Dynamic Health', and 'The New McDougall Cookbook'.

Founder of the 'McDougall Plan' for healthy living, this author has been studying and writing about the effects of nutrition on disease for over 30 years' according to information on his website.

In his books and through his website Dr McDougall advocates a diet that is even higher in carbohydrate than the diet recommended by Dr Ornish. According to Dr McDougall, 'A healthy diet...is more than 80% carbohydrate from nutritious foods -- starches, vegetables and fruits.' This contrasts with the current contribution of ~50% of carbohydrate to total kilojoule intake in Australia, and represents an extreme goal that few people in Western nations are likely to be able to maintain.

Dr McDougall's beliefs on the causes of overweight are orthodox (too much high-fat food, not enough starchy food and insufficient exercise). He recommends greatly increasing consumption of fruits and vegetables (as do all orthodox health authorities). However, he inappropriately advocates eliminating bread initially in the weight loss diet, and believes (wrongly) that most adults in Western nations cannot digest milk. He has also reported that at his clinic, 'average weight loss for overweight men is 5.3 pounds (2.4 kg) in 11 days, and women is about four pounds (1.8 kg) in 11 days'. These rates of weight loss correspond to about 6 kg per month -- a figure that greatly exceeds the rate of 0.5-1.0 kg per month recommended by Nutrition Australia as being safe and sustainable.

Summary
The basic nutrition Dr McDougall includes in his books and website articles is mostly sound, and his diet would very likely promote health and lead to weight loss, if people could motivate themselves to follow it. But his advice that more than 80% of kilojoule intake should be derived from carbohydrate is extreme and is unlikely to be maintained in the long term by most people in Western nations and his advice on the rate of weight loss is not in accord with current orthodox recommendations. 

THE PRITIKIN DIET
Like the Eat More Weigh Less diet of Dr Ornish, the first Pritikin diet was devised (by Nathan Pritikin in 1979) as an attempt to markedly reduce the risk of heart disease. A revised plan -- 'The Pritikin Weight Loss Breakthrough' -- was published by Nathan's son Robert in 1991. The revised Pritikin concept is similar to the diet of Dr Ornish, but in addition it disallows processed grains, and recommends slightly lower protein intake, with hardly any animal protein, eggs or fats allowed. This diet provides for a similar intake of carbohydrate as does Dr McDougall (~80% of kilojoules).

As applies to the Ornish diet, the diet has been shown to prevent and even reverse atherosclerosis when combined with stress reduction and exercise. The Pritikin diet is basically very healthy (although it ignores the nutritional benefits of lean meat and eggs), but it suffers from the same potential for non-compliance that is likely to apply also to the Ornish and McDougall diets.

Summary
Although placing inappropriate restrictions on lean red meat and dairy products, this diet is health-promoting overall and is likely to reduce both weight and the risk of heart disease. As with other extremely high carbohydrate diets, it may not be well-tolerated by people who are used to relatively high fat intakes. 

EIGHT WEEKS TO OPTIMUM HEALTH
Dr Andrew Weil is well known in the United States as an advocate of 'integrative medicine' (combining orthodox and alternative medicine) and for his 'Ask Dr Weil' columns (formerly in a magazine called 'Natural Health' and now available on-line).

Dr. Weil places emphasis on the 'fundamentals of health', which he defines as 'diet, exercise, peace of mind'. His recommendations are aimed at what has been termed 'holistic' health. That is, he aims to achieve not just an absence of disease, but 'positive health', including improved immunity against infections, reduced risk of degenerative diseases (such as heart disease, diabetes, cancer) and an 'inner strength and joy'.

Dr Weil believes that diet -- particularly the types of fat that are eaten -- plays a key role in this. In agreement with orthodox nutritionists he advocates reducing saturated fat intake, but he also believes that polyunsaturated fats -- specifically corn, safflower, soy, and cottonseed oils -- should also be avoided as far as possible. Instead, he recommends using olive oil as the only (or major) fat in the diet.

Dr Weil is correct in stating that there is good evidence for health benefits from increased consumption of olive oil. However, it is equally true that the oils he suggests avoiding are better sources than olive oil of an essential fatty acid (the 'n-6' series). The National Heart Foundation states that fats found in fish, nuts, poly- and mono-unsaturated margarines, cooking oils and salad dressings help lower cholesterol and fight heart disease. So it is probably at least premature, and may be inappropriate, for Dr Weil to recommend the exclusive use of olive oil. [For more information on fats and oils, see the FAQ entitled "What are the differences between fats and oils and what do the terms 'saturated', 'monunsaturated' and 'polyunsaturated' mean?" in this series].

In agreement with orthodox authorities Dr Weil recommends eating lots of fresh fruits and vegetables. This is sound advice. The Australian recommendation is to eat about five serves of vegetables and two of fruit per day (where one serve of vegetables is half a cup of cooked vegetables, one serve of fruit is a medium size piece of fruit (eg, apple, pear, orange, or two pieces of smaller fruit (eg, apricot, plum).

Dr Weil doesn't have a particular diet plan for weight loss, but says that the secret to successful weight loss is to 'eat less and exercise more' and to 'make an effort to replace high-fat foods with low-calorie (= low kilojoule) ones like vegetables'. His advice on weight loss is entirely in keeping with orthodox nutrition advice. This advice includes his suggestion to eat mainly low glycemic index foods. [For more information on this, see the FAQ entitled 'Glycemic Index' in this series]. Finally, he advocates moderating alcohol and avoiding artificial sweeteners and synthetic fat substitutes. He regards exercise as being vital to the achievement and maintenance of weight loss.

Most of the remainder of  his nutritional advice is 'orthodox', and Dr Weil is actually ahead of much of the field in his belief that optimum health and weight control have a spiritual/emotional component. For example, he recommends combating anxiety with relaxation exercises rather than food, and being accepting of your natural body shape if it is not threatening your health. This is in keeping with the World Health Organisation's definition of health as 'a dynamic state of complete physical, mental, spiritual and social well-being and not merely the absence of disease or infirmity'.

Summary
Dr Weil includes much of value in his recommendations, not only on diet but also on non-dietary aspects of health and wellness. However, his recommendation to avoid polyunsaturated fats and to use olive oil as the only (or at least predominant) form of oil in the diet is at least premature. 

GUTBUSTERS
Available in the form of a book and as a 'six week waist reduction program designed specifically for men', the GutBusters program was developed by a team led by Dr Garry Egger from Deakin University (Australia). The nutritional aspects of the program were devised by dietitian Rosemary Stanton. The reason for targeting men especially is that most diet programs have been designed to appeal to women, even though being overweight or obese is often more dangerous to health for men. This is because men have a greater tendency to put on weight in the abdomen (the area of the 'gut'). Abdominal body fat is strongly associated with increased risk of both heart disease and diabetes. However, although the target audience is men, the principles of GutBusters are just as appropriate for women.

The program sets out to inform men how they may best modify diet, alcohol intake and activity levels to reduce waist size. Reduction in fat intake (and a CORRESPONDING increase in carbohydrate intake) is advocated. Men are asked not to make any changes that they can't make permanently. This includes changes to alcohol consumption, so rather than banning alcohol, men are encouraged to 'trade off' each drink with extra walking or other physical activity. They are also encouraged not to combine alcohol with fatty foods. The emphasis is on foods that are hearty and filling.

The GutBusters program is very popular, and, unlike many other programs aimed at weight loss, it has been evaluated for its effectiveness in lowering body fat levels. A study reported last year showed a slight but significant drop in average waist circumference among nearly 900 men who took part in the program. There were also self-reported improvements in diet and a reduction in alcohol consumption.

The GutBusters program is a worthwhile and sensible attempt at reducing the level of abdominal body fat, especially in men, but the program can be followed equally well by women. It recognises the importance of satisfying people's desires as well as their needs. The book is written in an engaging style and includes many appropriate and amusing cartoons illustrating the points being made. There are also accompanying recipe books. 

Summary
The GutBusters program is highly recommended for overweight men (and women) who genuinely want to lose some of the body fat that they have accumulated (especially over the stomach) and keep it off.  

FINAL COMMENTS

It should also be noted that diet is only one aspect of lifestyle that affects health. Another vitally important one is physical activity. The recommended lifestyle for optimal health and wellness includes a diet based on a wide variety of nutritious foods (with the greatest emphasis on plant foods) and accumulating at least 30 minutes of moderate-intensity physical activity on most -- preferably all -- days. A good example of moderate-intensity activity is brisk walking at a pace where you are able to comfortably talk but not sing. Other examples including mowing the lawn, digging in the garden or medium-paced swimming or cycling. The 30 minutes of activity need not be carried out all at the one time. Three 10-minute blocks or two 15-minute blocks of activity are fine. An easy way of achieving the 30 minutes can be through finding ways of increasing incidental physical activity e.g., walking rather than driving short distances, taking stairs instead of the elevator or escalator, and so on. [For more information on the importance of activity see the FAQ in this series entitled  'What types of activities and activity levels are appropriate for general health and wellbeing?'].

See the other Popular Diet Frequently Asked Questions in this series:

Part One: High Protein Diets

Part Three: Other Diets 
(Neither High Carbohydrate nor High Protein Diets)

For more information Nutrition Australia recommends:

• Weight for Change
• Eating Activity Sport and You

 Back to Frequently Asked Questions Index

Disclaimer: This material is provided on the basis that it constitutes advice of a general nature only. It is not intended to replace the advice of a physician or a dietitian.

[Date issued: November 2000]