As explained in previous articles, too-strict dieting can actually be a cause of weight gain if calories are restricted over a long period of time. The seeming paradox is caused by a defence mechanism within the brain that lowers the metabolic rate when food is scarce. This system – designed to help us survive through seasonal food shortages – is no longer necessary to insure our survival, but nevertheless we must understand what triggers metabolic conservation if we are to break out of the vicious dieting cycle promoted in many women’s magazines. Even the writers of Redbook admit “losing weight is not always a simple process because dieting can cause the body to slow the burning of calories” (1). Additionally, “because dieting causes a drop in metabolism, fat loss slows to a whimper (even when you don’t eat much) and the fat threatens to return when you resume normal eating patterns” (2).
Recent studies have also shown that the same metabolism lowering effect can occur as a result of too much exercise. According to Chris Aceto of Muscle and Fitness, “Attempts to expend large amounts of calories [by exercising for hours at a time] causes a loss in lean body mass (muscle), slowing your metabolism to a crawl” (3). Strict dieting combined with excessive exercise is a double whammy that constitutes an eating disorder with significant health risks.
The result of a very low metabolism is that you will burn fewer calories throughout the day (this is your resting, or basal metabolism), and you will gain weight with fewer calories. This occurs because with strict dieting and/or too-intense exercise, “you may actually be training your body to be more efficient, thus allowing your metabolism to adjust to fewer calories and a higher energy output” (4). Studies have shown that anorexic women may have metabolic rates that are as much as 50% lower than normal (which may be explained by loss of muscle mass alone). “In addition, studies have shown that women on very-low-calorie diets (800 calories per day) who exercised actually suffered a greater slowdown of resting energy expenditure (60% of pre-diet measures) than women who dieted more moderately without exercise” (5).
In simple terms – you weigh more and more while eating less and less. You might shed 8 lbs on a crash diet, but you also might get fatter than you previously were when you go off the diet. This, combined with the bad habits that many popular fad diets teach (ie, large portions, very low calorie breakfasts, and eating packaged foods), can easily lead a slightly overweight woman down the road to obesity.
The key to overcoming the negative effects of this cycle is to diet in such a way as to preserve the metabolic rate, and to concurrently work to stimulate the metabolism to burn more calories while resting. There are a number of factors to consider.
Dieting To Preserve Metabolic Rate:
First, it is important to diet properly. A good diet must supply the body with sufficient calories and nutrients to provide energy for all of your activities. Too few calories makes the body conserve. However, we all know that in order to lose weight, we have to take in fewer calories than the body needs each day. The key here is moderation, and good food choices are also important. One weight loss system that is showing very good results is the product of a Swedish study from the Obesity Unit of Huddinge University Hospital. This cycle diet is based on the notion that calories may be safely restricted, as long as the restrictive period is short and normal eating resumes for a significant time after. The guideline is: “Reduce your calorie intake for two weeks, eat more reasonable portions for up to a month, then begin again” (6). The researchers found that:
Three two-week periods of very strict dieting separated by a month proved better than six weeks of continuous dieting. Initial fat loss was basically the same for all subjects, but the phased dieting produced less muscle fatigue and other side effects. Better yet, weight lost during the very-low-calorie phases stayed off when subjects went back to a less-restrictive low-calorie diet, even when it was for a whole month. Apparently, either two weeks was short enough to prevent some of the drop in metabolism that can occur with long-term dieting — and the dreaded “fat rebound” that comes after it — and/or metabolism was restored enough during the less-restrictive periods that fat regain was prevented. (7)
Swedish body-builder and medical expert Torbjorn Akerfeldt has had success with a similar plan that he sums up simply: “Eating big for 14 days, then small for 14 days, is better than eating medium for 28 days” (8).
Next week I will discuss another diet that works to maintain the metabolism, as well as how exercise and weight training can significantly increase the number of calories that you burn even at rest.
(1) Salisbury, N. (Sept. 1995). 6 ways to burn fat faster. Redbook, Sept 1995 v185 n5 p145(3).
(2) Rowley, B. (Spring 2001) The Two Week Diet: Stop Starving Yourself and Still Lose Bodyfat. Muscle and Fitness: Hers. vol. 2, no. 2. P. 98-103
(3) Aceto, C. (April 2002). Don’t be Cardio Crazy: Effects on metabolism of drastic caloric expenditures. Muscle & Fitness, April 2002 v63 i4 p34(1).
(4) Modugno, B. (Winter 2000). FAQs: Performance Nutrition. Muscle and Fitness: Hers, vol.1 no. 4, p.126-9
(6) Rowley, B. (Spring 2001) The Two Week Diet: Stop Starving Yourself and Still Lose Bodyfat. Muscle and Fitness: Hers. vol. 2, no. 2. P. 98-103
(7) Rossner, S. (1998). Intermittent vs. continuous VLCD therapy in obesity treatment. International Journal of Obesity and Related Metabolic Disorders 22(2):190-192
(8) Sports supplement review, 3rd issue, 261-286. Golden, CO: Mile High Publishing, 1997.