The Metabolism Myth

Drew, first, Ive never said that the reason people are overweight is because of a slow metabolism. You've totally misread me on that. People gain weight due to a caloric surplus.   In my book the Body Fat solution (avery/penguin), pge 35, I state that slow metabolism as a reason for inability to lose weight is a myth:

 "overweight people often claim that a slow metabolism is the reason they cannot lose weight. This has been disproven time after time in a variety of tightly controlled experimental research trials. Believe it or not, the reverse is true. Men and women with larger body mass actually burn more calories because their resting metabolic rate is directly linked to their total body mass and lean body mass. Simply stated, large people burn more calories than small people. Furthermore the energy cost of moving around a very large body is greater than the energy cost ofmoving a light body. As you lose weight, your calorie requirements go down inproportion to your total body mass. If you keep eating the same for your smaller body as you did for your larger (pre diet) body, your calorie deficit shrinks as you lose weight. this not only explains inpart, the slow metabolism myth, but it also helps explain weight loss plateaus and weight regain."

My favorite study to illustrate this point is steven lichtmans study from the NEJM (1992, 327(27) where he showed that "thyroid probems" and "slow metabolisms" were really just under reporting of food intake and over reporting of activity.

Next, Drew, you wrote

According to one of your many websites: Not only are there foods that speed metabolism, there are others that limit your "metabolic efficiency". Find me a reputable scientist that agrees with this sentence...  and we'll set up the discussion.

I don't believe in magic foods that invalidate the law of energy balance. It takes an energy deficit to lose weight. However, i do often state that protein foods have a higher thermic effect than other macronutrients, which affects the size of the energy deficit both via thermogenesis and satiety. Westerterp-Plantenga (Dietary protein, metabolism, and body-weight regulation: dose-response effects.Int J Obes . 2006) writes that protein's effect on thermogenesis and energy efficiency is one of the factors that play a role in increased weight loss due to protein metabolism and the building of lean tissue.

Granted,  this may not be hugely significant in isocaloric diet comparisons in the short term, but it is enough to be measureable and is likely significant over time and moreso with the higher protein intakes commonly used in bodybuilding-style diets.  see Thomas Halton in "The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review" (J am coll nutr 2004), which says, "convincing evidence exists that protein exerts an increased thermic effect when compared to fat and carbohydrate."

when combined with the increased satiety provided by higher protein intakes (30% as compared to 15% of total calories, for example - as in Weigles 2005 AJCN study), the difference inweight loss does become significant.

It's on the exercise and activity side that we really have the opportunity to increase metabolism. If metabolic rate is total daily energy expenditure (TDEE), then TDEE is the sum of basal metabolic rate (BMR), thermic effect of exercise, (TEE), non exercise activity thermogenesis (NEAT) and thermic effect of food (TEF).

If you increase BMR, you've increased metabolism. If you increase your caloric expenditure through training (TEE), you've increased your metabolism. If you increase NEAT by moving more throughout the day, youve increased metabolism, have you not? With training that's intense and training which increases lean body mass, you've substantially increased metabolism short term via calories expended during exercise and via EPOC and long term via increase in lean body mass.

So even supposing our influence on TEF with shifts in macros is very small (admittedly it is), how can you say that you can't increase metabolism? Of course you can! Increasing metabolism simply means increasing energy expenditure. thats my philosophy:  burn the fat, feed the muscle; eat more burn more. No magic is implied; Im suggesting that we avoid a diet-only/starvation approach which achieves a caloric deficit with severe food restriction while remaining mostly sedentary, and instead we take up serious training: serious weight training to build muscle and cardio to widen the caloric deficit further and improve cardiovascular health.

we can also protect ourselves from large adaptive decreases in metabolism by avoiding excessive and prolonged caloric deficits and taking a slow and steady approach to weight loss.  "metabolic damage" may not be a scientific term, but this refers to the adaptive thermogenesis, which is the scientifically proven reduction in metabolic rate NOT accounted for by the drop in total body mass. See Abdul Dulloos studies, including "adaptive reduction in basal metabolic rate in response to food deprivation in humans", doucets studies, "clinical significance for adaptive thermogenesis," "evidence for the existence of adaptive thermogenesis during weight loss" and very recently, Redman et al's study "metabolic and behavioral compensations in response to caloric restriction: implications for the maintenance of weight loss (PLOS one feb 2009). their conclusion: "in response to caloric restrcition we observed a true metabolic adaptation at months 3 and 6 of the intervention." There was also a behavioral adaptation as NEAT and TEE dropped.

There's no shortcuts; its about calories in vs calories out, but we can affect the energy balance equation (metabolism): for the worse by starvation dieting, losing lean body mass and being sedentary and for the better by training, increasing energy expenditure and building lean mass. Thats what I teach and thats what I practice as a natural bodybuilder.