How dietary carbohydrates cause weight gain

Part 6: Eat fat, get thin

If we are to overcome the obesity epidemic we must reject outright ideas that have been shown to be unproductive. That means abandoning starvation-type, calorie-controlled diets for something that has been shown to work: low-carb, high-fat diets.

Low-carb diets are said, by those with scant knowledge of the subject, to be a recent dietary fad with no long-term evidence in their support. Nothing could be further from the truth: they have actually been around for over 140 years. (And that is without counting anthropological studies of our ancestors or modern hunter-gatherer cultures.)

It is almost a century and a half since a Londoner, William Banting, wrote the first low-carb diet book entitled Letter on Corpulence Addressed to the Public . Banting had been plagued by obesity for over 30 years and suffered an increasing number of other complaints. The doctors of the day were no better at treating obesity than are today's nutritionists. Then Banting met a Dr William Harvey, FRCS. Harvey put Banting on a low-carb diet, and within a year all his ailments 'passed into a matter of history'. Since then, inspired by Banting, many studies have shown over and over again that a low-carb, high-fat diet is the best way to lose weight and, more importantly, maintain that lower weight.

An early study was conducted at the Royal Infirmary, Edinburgh. Drs. D. M. Lyon and D. M. Dunlop noticed that healthy adults maintained an almost constant body weight over long periods, in spite of considerable variations of physical activity and of food intake. They further noticed that those who regularly overate did not necessarily become overweight; neither did those who had a poor appetite necessarily become thin.

During 1931 they conducted a controlled dietary trial using a large variety of low- and high-calorie diets, ranging from 800 to 2,700 calories.[1] So that comparisons would be more meaningful, all the patients were put initially on 1,000-calorie slimming diets. On the low-calorie diets, average losses were found to depend not on the calorie content of the diets but on the carbohydrate content. The average daily losses on the 1,000-calorie diets were:

• high carbohydrate/low fat diet - 49 g (like the modern slimming diet)
• high carbohydrate/low protein - 122 g
• low carbohydrate/high protein - 183 g
• low carbohydrate/high fat - 205 g (like the regime suggested here)

It was expected that on the 1,700 to 2,700-calorie diets patients would not lose weight. In fact all but three did lose weight. Lyon and Dunlop, in their conclusions say: 'The most striking feature . . . is that the losses appear to be inversely proportionate to the carbohydrate content of the food. Where the carbohydrate intake is low the rate of loss in weight is greater and conversely'.

There have been many such trials and they still continue today: Published in the year 2000, a prospective study was conducted to evaluate the effect of a low carb, high-protein/fat diet in achieving short-term weight loss.[2] Researchers at the Center for Health Services Research in Primary Care, Durham, North Carolina, reported data from a 6-month study that included 51 individuals who were overweight, but otherwise healthy. The subjects received nutritional supplements and attended bi-weekly group meetings, where they received dietary counselling on consuming a low-carbohydrate, high-protein/fat diet.

After 6 months, they had lost, on average, more than 10% of their weight and their total cholesterol dropped by an average 10.5 mg/dl (0.27 mmol/L). Twenty patients chose to continue the diet, and after 12 months, their mean weight loss was 10.9% and their total cholesterol had decreased by 14.1 mg/dl (0.37 mmol/L). Dr William S. Yancy, who led the study admitted that:

'This study of overweight individuals showed that a low carbohydrate, high-protein/fat diet can lead to significant weight loss at one year of treatment.'

All these recommendations and evidence could have saved a great deal of grief, trauma and ill-health if two other doctors had been listened to in 1994. Professor Susan Wooley and Dr David Garner highlighted the professional's role in people's increasing weight, saying:[3]

'The failure of fat people to achieve a goal they seem to want - and to want above all else - must now be admitted for what it is: a failure not of those people but of the methods of treatment that are used.'

In other words, blaming the overweight for their problem and telling them they are eating too much and must cut down, is simply not good enough. It is the dieticians' advice and the treatment offered that are wrong. Wooley and Garner concluded:

'We should stop offering ineffective treatments aimed at weight loss. Researchers who think they have invented a better mousetrap should test it in controlled research before setting out their bait for the entire population. Only by admitting that our treatments do not work - and showing that we mean it by refraining from offering them - can we begin to undo a century of recruiting fat people for failure.'

But there is a 'better mousetrap'. William Banting wrote of it nearly a century and a half ago.

References

1. Lyon DM, Dunlop DM. The treatment of obesity: a comparison of the effects of diet and of thyroid extract. Quart J Med 1932; 1: 331.

2. Yancy WS. New research examines effectiveness and weight loss maintenance of the low carbohydrate diet . NAASO 2000 - Annual Scientific Meeting, Long Beach, California. 30 October 2000.

3. Wooley SC, Garner DM. Dietary treatments for obesity are ineffective. BMJ 1994; 309: 655.