By Anssi Manninen, MHS
It’s not just how much body fat you have that’s a health risk, it’s where the fat is. Guys with abdominal fat are much more likely to develop heart disease and diabetes than those with fat on the hips. In addition, most people aren’t too excited about ”love handles,” so nobody wants to look like the Michelin Man.
Some old-school nutritionists argue that fat loss or fat gain is all about calories – that a calorie is a calorie no matter what the source. Well, frankly, that’s utter nonsense.
While total calories do play a part, it’s not just the caloric content of the food we eat, it’s also what those calories do to us metabolically.
THE STUDY
Dr. Jytte Halkjaer and colleagues at Copenhagen University Hospital investigated the association between macronutrients (i.e., carbs, proteins, fats) and subsequent changes in waist circumference in a large, population-based cohort of middle-aged women and men. The results revealed that total energy intake or total fat intake wasn’t significantly associated with the subsequent differences in waist circumference. However, the investigators noted that vegetable fat promotes fat accumulation.
Intake of carbs from vegetables and fruits prevented fat accumulation. However, intake of carbs from refined grain and potatoes clearly promoted fat accumulation. A similar but insignificant pattern was found for carbs from whole grain. Proteins, especially animal proteins, prevented fat accumulation.
A MISINTERPRETED STUDY
Another study, published in The Journal of the American Medical Association, examined the long-term effects of an ad libitum low-fat/high-carb diet on bodyweight. The results indicated that after losing 2.2 kilograms in the first year, the subjects maintained a modest weight loss compared with the control group during an average 7.5 years of follow-up and showed no increase from their baseline weight at any point during the study. The study’s author, Dr. Barbara V. Howard, PhD, president of MedStar Research Institute, said her study refutes claims that high-carb diets are partly behind America’s obesity epidemic. However, this is a misleading statement.
The difference in caloric intake between the low-fat/high-carb group and the control group (who ate whatever they wanted) was about 120 kcal per day. If we multiply this 120 kcal per day times 365 days per year times nine years, we find that over the course of the study, the subjects in the low-fat/high-carb group apparently consumed almost 395,000 fewer calories than did the control group. Yet, the difference in weight loss was pretty meaningless. Furthermore, the high-carb/low-fat group added about 1.6 centimeters to their waist circumferences, indicating that they actually gained adbominal fat while losing lean body mass (i.e., muscle and bone mass).
To put it simply – when it comes to body composition improvements, a high-carb diet isn’t the way to go. People should eat less carbs and more protein than recommended by misinformed health ”authorities.”
References:
1. Halkjaer J et al. Intake of macronutrients as predictors of 5-y changes in waist circumference. Am J Clin Nutr, 2006 Oct;84(4):789-97.
2. Howard BV et al. Low-fat dietary pattern and weight change over 7 years: the Women’s Health Initiative Dietary Modification Trial. JAMA, 2006 Jan 4;295(1):39-49.
