Diet Fads - Use Them to Advantage!

Summarized by Robert W. Griffith, MD
April 15, 2005

Introduction

The 'father' of the low-carb craze was Dr William Banting, writing in his pamphlet "A Letter on Corpulence, Addressed to the Public", which was published in 1864. Banting described a low-carbohydrate diet that enabled him to lose 46 pounds in a year. Dr Atkins diet came much later.

There have been several reports recently about the individual effectiveness of different fad diets. (One is summarized in the first link below.) It seems that there isn't much to choose between low-carb, low-fat, balanced fat-carb ratio diet, and calorie restriction. All are effective in the short term, but there are high drop-out rates and 'lapses'.

An editorial by Dr George Bray in the Annals of Internal Medicine has reviewed some of the reports concerning studies on the Dr Atkins diet - i.e. low carb diets. Here's a summary of his views.

How a low-carb diet works

A 2-week study has shown that with a low-carb diet (with unlimited protein and fat), calorie intake decreased by a third (from over 3,000 calories to just over 2,000 calories a day).¹ What's important is that drastically reducing the amount of carbohydrates was not immediately accompanied by replacement of the calories by increased intake of protein and fat. Several months are required before this sort of compensation occurs.

What's common to all diets

A common feature of all fad diets is a reduction in food choices. It's been shown that once people have eaten their fill at a buffet of one type of food, they still have room for other types of food. This explains why we always seem to have room for dessert, even after we've stuffed ourselves with the appetizers and the entrée. Limiting one type of food will not automatically lead to an increase in intake of other food types. Scientists call this "sensory-specific satiety".

There's another common feature - any diet that reduces energy intake (calories) relative to energy expenditure will decrease body weight, as energy must be withdrawn from body fat stores. The level of adherence to the diet is the best predictor of weight loss.

How having different diet plans can help

With all diets, body weight plateaus after the initial weight loss; indeed, it becomes difficult for the patient to maintain their weight loss. This leads to considerable frustration. But remember the sensory-specific satiety effect, described above. This limits food intake by lowering the desire to eat more of the type of food just eaten. As all diets limit one or more food choices, they will all have an initial weight loss effect, until the body overcomes their particular sensory-specific satiety effects. Switching between different diets with different targets for restricted intake may, in fact, be a solution to long-term management of overweight problems.

This means we shouldn't mock people following fad diets as being irresolute butterflies; such people may have found a way to keep the pounds off while still enjoying a variety of different food types - which change every 2-3 months.

Source

• Is there something special about low-carbohydrate diets? GA. Bray, Editorial. Ann Intern Med, 2005, vol. 142, pp. 469--470

Footnotes
1. Effect of low carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes. G. Boden, K. Sargrad, C. Homko,  et al., Ann Intern Med, 2005, vol. 142, pp. 403--411

Related Links
It's Not Which Diet, It's How You Diet
Rating Your Food Behaviors
Overweight Baby Boomers at Risk of a Poor Quality of Life, Later
In the Battle Against Weight, It's All About Maintenance

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