The validity of the low-fat/high-carb diet is challenged when those most knowledgeable in its application succumb to diseases it is meant to prevent. For example, Dr. Lynn Alan Smaha, a former president of the American Heart Association (AHA), died recently, felled by a heart attack after his daily run. He was only 63. Dr. Smaha almost certainly followed a diet very low in saturated fat and cholesterol and high in carbs. Evidently, it didn't help him at all. Indeed, recent studies have clearly refuted the hypothesis that a low-fat/high-carb diet decreases risk of heart disease. When in comes to body composition, gym rats and fitness babes already know what science is now showing; replacing carbs (especially refined carbs) with protein and fat is an effective way to promote fat burning while sparing muscle mass, so it would be wise not to follow the dietary guidelines of the AHA or the American Dietetic Association. This article will examine the latest findings on macronutrients.
A New Study: Moderate-Carb vs. High-Carb
A recent study at Skidmore College examined the effectiveness of two lifestyle modification programs of exercise training and nutritional intake on improving body composition and disease risk in overweight/obese men and women. Sixty-three subjects were weight matched and assigned to one of three groups for a 12 week intervention: 1) high-intensity resistance and cardiovascular training and a moderate-carb/high-protein diet (40% carbs, 40% protein), 2) moderate-intensity cardiovascular training and a high-carb AHA diet (50 to 55% carbs; 15 to 20% protein, < 30% fats), and 3) an inactive control group. The results of this study indicated that
1. A moderate-carb/high-protein diet resulted in more favorable changes in body composition (percent body fat -15.8% vs. -6.9%; abdominal fat -15.6% vs. -7.5%) compared to the AHA diet and control group.
2. Total cholesterol, LDL-cholesterol, and blood pressure declined in a moderate-carb/high-protein group, whereas the AHA diet and control groups remained unchanged. In other words, AHA diet was absolutely ineffective.
Importance of Post-Exercise Protein Supplementation
The purpose of the recent study by Dr. Ryan Andrews and colleagues was to examine whether variability of protein intake from food was associated with variability in lean mass gains with resistance training in the context of post-exercise protein supplementation. The study hypothesis was that consuming a fair amount of protein immediately after a workout would reduce the effect of habitual intake of protein from food on muscle mass gains with resistance training. 22 men and 30 women ranging in age from 60 to 69 years participated in a moderate 12-week resistance training program. At each resistance training session, subjects consumed a post-exercise drink containing 0.4 grams of protein per kilogram of lean mass plus some carbs and fats. The results indicated that variability in mean daily protein intake was not associated with change in lean body mass, suggesting that post-exercise protein supplementation is more important than total daily protein intake. However, young gym rats engaged in serious resistance training likely benefit from higher daily protein intake (i.e., 2 grams of protein per kilogram of body weight). Whatever the case, this study provides additional support for the importance of post-exercise supplementation. The results are in line with the earlier study by Dr. Roy and co-workers, who reported that the provision of a protein-containing post-exercise supplement resulted in a more positive nitrogen balance as compared to the same amount of protein provided in the morning. In summary, post-exercise protein supplementation is critical for muscular development. I strongly suggest that you consume a serving of BioQuest MyoZene immediately after each resistance exercise session. MyoZene contains rapidly acting whey protein hydrolysate and a host of other beneficial ingredients.
New AHA Dietary Guidelines: Where is the Evidence?
Recently, the AHA nutrition committee updated recommendations it issued in 2000. Not only does the AHA set a number for trans fat, but it also advises decreasing saturated fats to 7 percent of total calories. While trans fat recommedantion is supported by scientific evidence, demonization of saturated fats lacks scientific basis. Simply put, there is no evidence that reducing saturated fat intake to less than 7% of daily energy will prevent chronic diseases or increase life expectancy. In fact, such a limitation will reduce intake of high-quality proteins and reduce the absorption of fat soluble vitamins.
Interestingly, it appears to be impossible to even design a menu that meets the AHA guideline restricting saturated fat to less than 7% of total calories while also meeting all essential nutrient requirements and simultaneously remaining within the AHA guidelines for cholesterol, sodium and types of foods to include (or avoid). Just Check Regina Wilshire's "The $1000 Challenge": http://weightoftheevidence.blogspot.com/2006/06/new-aha-diet-lifestyle-recommendations.html
In summary, the AHA dietary guidelines are pretty much a population-wide experiment without consent.
About Anssi Manninen Anssi Manninen holds an M.H.S. in sports medicine from the University of Kuopio Medical School. His numerous cutting-edge articles in Muscular Development firmly established his reputation as a leading authority on hard-core sports nutrition. Anssi?s articles have also been published in scientific journals, including The British Journal of Sports Medicine, The Journal of International Society of Sports Nutrition, Nutrition & Metabolism, and Journal of Sports Science and Medicine. Anssi is also an Associate Editor for Nutrition & Metabolism, a leading scientific journal in the area of nutritional biochemistry.
References 1. Wortman J. Health promotion when the 'vaccine' does not work. Health Promot J Austr. 2006;17:91-6.
2. Arciero PJ et al. Increased dietary protein and combined high intensity aerobic and resistance exercise improves body fat disribution and cardiovascular risk factors. Int J Sport Nutr Exerc Metab. 2006;16:373-392
3. Andrews RD et al. Protein Intake for Skeletal Muscle Hypertrophy with Resistance Training in Seniors. Int J Sport Nutr Exerc Metab. 2006;16:362-372.
4. Roy BD et al. The influence of post-exercise macronutrient intake on energy balance and protein metabolism in active females participating in endurance training. Int J Sport Nutr Exerc Metab. 2002;12:172-88