Carbohydrate-Guide

The Science of Using Food to Increase Metabolism. Have you ever found yourself sweating after a big meal? Thermogenesis is a central feature of the fat-burning potential of food. Specifically, the “thermogenic,” or “thermic,” effect of food refers to the calorie-burn associated with digestion and assimilation of food. In other words, every food contains energy but also requires an expenditure of energy when eaten and digested.

Ever found yourself sweating after a big meal?

• This is dietary-induced thermogenesis in action. In effect, you are exercising - not by moving your limbs, but by the activity that is going on inside your body to break down and process the food that you ate.

The thermogenic effect of food peaks within one hour after a meal is consumed, and can be quite substantial in terms of the amount of energy dissipated. The magnitude of the thermogenic effect of food ranges 10%-35% of ingested calories, and varies depending on the type of food eaten and individual metabolic differences.

Of the three macronutrients, protein outdistances both fat and carbohydrate as a thermogenic stimulant due to the caloric cost incurred in processing amino acids. This is one reason why protein is the centerpiece of many popular diets.

A meal of pure protein elicits a thermogenic effect amounting to approximately 30% of the meal’s total calories, about twice as much as carbohydrate, and more than three times as much as fat.

In other words, next time you look at the label on a package of lean meat, you can automatically subtract 30% of the calories.

Reducing “Actual” Calories

The actual caloric content of a food can be determined by subtracting the caloric “cost” of a food from the total amount of calories that it “pays” into your system.

The concept here is a simple one:

Any calories that get burned-up as a result of eating no longer exist, and thus cannot possibly be turned into bodyfat. These “disappearing calories” must be accounted for and should be maximized.

Actual Calories = Total Calories* - Caloric “Cost” of Digestion/Assimilation **

So which foods are highly thermogenic?

This question brings us back to “You Can Learn a Lot from looking back at our ancestors. Most of the ancestoral foods were highly thermogenic.

By contrast, processed high-density carbohydrate foods, a dietary staple for most Americans, occupy the opposite end of the spectrum, with a lot of “total calories” relative to “caloric cost” and thus not much of a thermogenic effect.

Take white bread, for example. It has been so extensively degraded by processing that your body’s work has been done for it by the manufacturer of the food. Your body does not have to work (i.e., pay a caloric cost), because the food is already broken down.

One way to estimate the thermogenic value of a particular food is to assess how much work you must do from the time you put the food in your mouth until you swallow it (This the “chew test”). This parallels the amount of energy that will be expended during the balance of the digestive process. When comparing the thermogenic effect of different foods, be sure to compare quantities of equal caloric value.

Bearing this in mind, let’s compare 100 calories worth of white bread with 100 calories worth of steak. The steak requires quite a bit of chewing, whereas the white bread practically dissolves in your saliva with very little chewing required - similarly to cotton candy. What about steak vs. ground beef? Steak wins - do you know why?

Because ground beef has been processed and, as I mentioned a moment ago, processing diminishes the thermogenic value of food.

What about apple vs. banana? This one is a closer call, but the apple wins - do you know why? Because an apple has almost twice as much fiber per ounce.