YOU CAN'T WIN. YOU CAN'T BREAK-EVEN. YOU can't get out of the GAME! (Part 1)
By Herve Bensabat
Montreal City, Canada  

Any frequent visitor to the local casino can recite the three cardinal rules of gambling. So too, can the wheeler-dealer Wall Street types who readily play the stock market for fast gains. Luckily, the average person possesses the common sense to safeguard the things that matter most in life. But if most people are reticent about risking their hard-earned savings, why are so many of them ready to gamble with their health?

As of July 2005 it is estimated there are 295,734,134 people living in America. Of those, 45% of adult women and 25% of adult men are on a diet on any given day spending over $40 billion on dieting and diet-related products each year. If that is n o t cause enough for worry, consider the following as well: 46% of 9 to 11 year-olds are "sometimes" or "very often" on diets and an astonishing 81% of them are afraid of being fat.

Perhaps the saddest statistic of them all is that a full 95% of all dieters will regain their lost weight within 1 to 5 years. This naturally begs the question, do diets work and how is weight change achieved?

The Health and Fitness Professional's Guide to Weight Change

The widely held belief perpetuated in the popular and technical literature presents the notion that body weight is controlled by the number of calories ingested versus the number of calories expended and is often justified by an appeal to the laws of thermodynamics. This can easily be corroborated by reviewing publications of such agencies as the U.S. Department of Health and Human Services, National Institutes of Health, American Heart Association, National Heart, Lung and Blood Institute and other organizations such as the American College of Sports Medicine who publish Position Stand papers on the subject.

Additionally, references are often made to a pound of fat equalling 3500 calories and a pound of muscle equalling 2500 calories, thereby dividing these figures by seven days in a week to produce a one pound weight change.

A Calorie is a Calorie is a Calorie…

Proponents of this approach will tell us that the first law of thermodynamics dictates that body mass remains constant when caloric intake equals caloric expenditure. Therefore to achieve weight change, a caloric imbalance needs to be created. This simplistic mathematical approach using the basic tenets of thermodynamics can be illustrated by the following equation:

According to this equation, a person seeking to lose weight must eat less and exercise more. If this is so, then the opposite must also be true for a person seeking to gain weight.

The trouble with manipulating calories in this fashion is its inherent assumption that all calories are created equal. So long as a caloric deficit or caloric surplus is created, then weight change will be achieved irrespective of other factors such as calorie composition or macronutrient profile, for example. In other words, applying this approach presupposes that diets of equal caloric content will result in identical weight change for everyone. The logical extension to this train of thought is to conclude therefore that a calorie is a calorie is a calorie.

Or is it?

The purpose of this article is to present dissenting views in the industry illustrated through the use of research studies published in nutritional journals in recent years. Personal convictions aside, no stand will be taken either for or against the positions presented. The objective is merely to provide the reader with an appreciation of the complexities involved in achieving weight change.

FOOD FOR THOUGHT- The limits of calorie counting; a brief overview

Calorie counting assumes all foods are used by the body in the same way and at the same rate. If a calorie is a calorie the composition of a meal would not matter much so long as the appropriate number of calories are accounted for. If calorie counting is the only factor necessary for weight change then eating 500 calories of ice cream and donuts would result in the exact same weight change and body composition as eating 500 calories of vegetables with a banana.

Strictly from an energy standpoint, calories represent a measure of heat used to express the energy value regardless of the food source, hence 500 calories from either source will produce 500 calories of energy.

However, extracting energy from ingested nutrients requires different metabolic and hormonal processes and many studies in the literature have demonstrated that ingesting equal amounts of calories with different macronutrient profiles result in varying body composition changes.

One such study conducted by Volek et al. examined the effects of a 6-week carbohydrate-restricted diet on total and regional body composition using 20 healthy normal-weight men (8 of them serving as a control group). The 12 men switched their diet from 48% carbohydrate to 8% carbohydrate (ketogenic diet) while the control group maintained their normal diet.

After the 6-week experimental period, fat mass dropped by 7.5 lbs with a concomitant increase in lean body mass (LBM) of 2.4 lbs. The researchers also tested for fasting hormone concentrations and found a significant decrease in serum insulin (-34%) and an increase in total thyroxine (T 4 )(+11%) and the free T 4 index (+13%). They found no significant changes in glucagon, total or free testosterone, sex hormone binding globulin (SHBG), insulin-like growth factor-1 (IGH-1), cortisol and triiodothyronine (T 3 ).

Additionally, the control group showed no changes in body composition or hormones. The researchers concluded that a carbohydrate-restricted diet resulted in a significant reduction in fat mass with an accompanied increase in LBM in normal-weight men and attributed 70% of the variability in fat loss by the decrease in serum insulin concentrations.

Another study examined the efficacy of 2 weight loss isoenergetic diets consisting of 7100 kJ (1690 Kcal) using 24 women for 10 weeks dividing the women into 2 groups; a carbohydrate group consuming 50 g F- 68 g P- 242 g C (macronutrient ratio of 27% F- 16% P- 57% C) and a protein group consuming 50 g F- 125 g P- 185 g C (macronutrient ratio of 27% F- 30% P- 43% C). The researchers Layman et al., found that the carbohydrate group (CHO) lost 6.96 kg (+/- 1.36 kg) while the protein group (PRO) lost 7.53 kg (+/- 1.44 kg).

In terms of body composition the PRO group showed a significantly higher loss of fat to lean weight (6.3 kg) than the CHO group (3.8 kg). While both groups showed reductions in serum cholesterol (~10%), the PRO group also showed significant reductions in triacylglycerols (triglycerides) (21%) and the ratio of triacylglycerols/HDL cholesterol (23%). The CHO group had higher insulin responses and postprandial hypoglycemia whereas the PRO group reported greater satiety.

Hence the researchers concluded that increasing the proportion of protein to carbohydrate in the diet of adult women has positive effects on body composition, blood lipids, glucose homeostasis and satiety during weight loss.

More recently, in June 2005 Noakes et al., studied 100 overweight women to evaluate the effects of a diet with a high ratio of protein to carbohydrate during weight loss on body composition. The women were randomly assigned to 1 of 2 isocaloric 5600 kJ (1335 kcal) diets either high in protein (HP) or high in carbohydrate (HC). While weight loss was 7.3 kg (+/- 0.3 kg) or 16 lbs for both groups, the HP group lost more fat mass (6.4 kg vs. 3.4 kg for the HC group) and triacylglycerols concentrations decreased more with the HP group compared to the HC group (0.30 mmol/L vs. 0.10 mmol/L respectively). The researchers concluded an energy-restricted, high-protein, low-fat diet provides nutritional and metabolic benefits that are “equal to and sometimes greater than those observed with a high-carbohydrate diet”.

And now a message from our sponsors

Like anything else, one should always apply prudence when reading about research studies. A good research experiment can always be independently replicated by other researchers and under properly controlled conditions ought to lead to the same conclusions. An important aspect to consider is the source of funding of the study, affiliations or competing interests the authors may have to establish a possible conflict of interest. For example, the study by Volek et al., is supported by a grant from the Atkins Foundation, New-York, N.Y.- without necessarily inferring a conflict of interest, it is important to note none-the-less.

While proper construction and methodology are obvious factors to watch for, one should also bear in mind that which ever side of an issue is presented, a study can always be found to promote that particular point of view.

Case in point. In April 2005 Sargrad et al., conducted a study to evaluate changes in carbohydrate or protein diets on weight, insulin sensitivity, glycemic control, cardiovascular risk factors and renal function in obese patients with type 2 diabetes. Six patients were randomly assigned a high-carbohydrate (HC) diet (30% F- 15% P- 55% C) and six others to a high-protein (HP) diet (30% F- 40% P- 40% C). The researchers found that both the HC group and HP group lost weight (2.2 kg or 4.4 lbs and 2.5 kg or 5.5 lbs respectively) and the difference between the groups was not significant. After 2 months, each diet had either no or minimal effects on lipid levels, renal or hepatic function.

Part 2 next month: Thermodynamics

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