A Calorie is not a Calorie
02-25-2008 01:58 PM
A Calorie is not a Calorie
The Thermic Effect of Food.
"Thermic effect of food (also commonly known simply as thermic effect when the context is known), or TEF in shorthand, is the increment in energy expenditure above resting metabolic rate due to the cost of processing food for storage and use.1 It is one of the components of metabolism along with the resting metabolic rate, and the exercise component. Another term commonly used to describe this component of total metablisom is the Specific Dynamic Action or SDA. A common number used to estimate the magnitude of the thermic effect of food is about 10% of the caloric intake of a given time period, though the effect varies substantially for different food components. Dietary fat is very easy to process and has very little thermic effect, while protein is hard to process and has a much larger thermic effect.2
Raw celery and grapefruit is often claimed to have negative caloric balance (requiring they take more energy to digest than usable energy received from the food), presumably because the thermic effect is greater than the caloric content, due to the high fibre matrix that must be unraveled to access their carbohydrates. There is no supporting evidence for these claims.
The thermic effect of food is increased by both aerobic training of sufficient duration and intensity and by anaerobic weight training. However, the increase is marginal, amounting to 7-8 cal per hour.1 The primary determinants of daily TEF are the quantity and composition of the food that's ingested."
The hormal responses from diet. "Metabolic Advantage."
Getting more of the right kind of macro's like certain fats, while reducing or eliminating the ability to gain fat on the diet can be considered a metabolic advantage. Increase anabolic hormones through diet. (See: Anabolic Diet, CKD Diets)
The principle of volumetrics when eating foods, or the "sated" feeling.
Simply low-energy foods that fill you up.
"Volumetrics is said to be the solution for the “contending schools of diet,” low-carb and high-carb. There are multiple diets and nutritionists which support both method types, though Dr. Roll says they should not focus on carb-intake, but rather satiety inducing foods."
That being said, all of these things are secondary to Energy Balance = Calories in - Calories out.
02-27-2008 01:35 PM
This is a contextual argument. The problem lies with caloric accounting. If protein's gross energy content is four calories per gram but if 25% of that is required for metabolizing the energy then the net energy available is only three calories per gram.
If the efficiencies (eg. thermic effects)of different sources are not the same then the energy input quantities are not comaparable. Quantities after losses must be considered.
02-27-2008 11:22 PM
You're only arguing part of what I'm posting, so 'no' doesn't seem to apply here.
A "not bad, but" would be a bit nicer.
02-28-2008 12:58 AM
You are correct. I should have been more specific. The 'no' is directed at the title of the thread. Also don't take it personally. I have seen the expression used in published articles so I am not suggesting that you originated it.
Being a science grad, I get a little frustrated with diet gurus that try to reinvent the wheel while simultaneously disregarding established and proven fundamentals. For the purpose of performing work at all but intense levels a calorie is a calorie. Of course body comp can be affected by how and from what those calories are obtained.
Your other points are on track but to add to the discussion here are my comments.
As for the hormone response, if a deficiency in a nutrient leads to a inferior hormone level does a surplus always result in a superior level or merely the normal level determined by genetics? The body has a lot of limiters in place that take effect when nutrition is optimized. Trying to skew one's diet to break those limits may not be successful. This is where hormone supplementation comes in. If the body wanted to achieve max testosterone levels, would it suffer from negative feedback from steroid use?
Satiety is definitely a useful tool for dieting. Lower energy density foods do provide more of a full feeling and whole foods tend to provide a longer duration energy supply. However when your body realizes that it is in an energy deficit it will still send a hunger stimulus...
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