You've seen the titles of books & magazine headlines: "Fat Burning Foods"; "Eat More to Weigh Less" and it goes on & on. So what are these articles & books trying to teach us? THey're trying to get us to use the Thermic Effect of Food (TEF) to burn more calories, and yes, it does work.
Thermic Effect of Food Defined : "the increment in energy expenditure above resting metabolic rate due to the cost of processing food for storage and use" or, the number of calories our bodies use in eating.
Yes, we burn calories by eating.
NancySBrandt : I'm thinking this #bodybugg thing might be too good to be true. How can I have 747 calorie deficit after eating fast food for two meals?
bodybugg : @ NancySBrandt Ucould eat donuts all day &still hv a calorie deficit! it doesn't mean tht it's a good thing. Uburn fewr K digesting fast food
I had the above conversation on Twitter & when I was looking through my blog posts to refer her to a resource, I realized that I had never written about the Thermic Effect of Food - even though I talk about it all the time.
Starting at the beginning, we consume calories through 3 macronutrients: Protein, Carbohydrates, and Fat. Macronutrients are compounds that we need on a large scale. Micronutrients (minerals and vitamins) are compounds that we need on a smaller scale (milligrams versus grams).
Each gram of Protein & Carbohydrate contain (roughly) 4 calories. Each gram of Fat contains 9 calories and each gram of alcohol (not a macronutrient, but a source of calories) contains 7 calories.
Your body uses about 3% of fat calories to convert that fat into energy. So, out of every 100 calories of fat consumed, you really take in 97.
Your body uses anywhere from 7 - 20% (more on this later) of carbohydrate calories to convert your carbohydrates into energy. So, out of every 100 calories of carbs ingested, you really consume 80 - 93.
Now protein is where things get interesting; your body uses 30% of protein's calories in processing those calories. Therefore, out of every 100 calories of protein consumed, you really only get the energy from 70.
In addition to the post I wrote on water weight , you can now see why folks who adopt a high protein diet drop weight very effectively for the same calorie burn:
Their body is using more of the calories consumed to process the food
Their body isn't storing the water along with the carbohydrates previously consumed
So, I'd like to revisit my earlier statement that the thermic effect of carbohydrates ranges anywhere from 7 - 20%. Why is there such a discrepancy? It really has to do with the thermic effect of processed foods & refined grains .
When food manufacturers process foods, they make it easier for your body to absorb those calories; your body doesn't have to work as hard to convert the carbohydrates to energy that your body can use. Some of the ways that they "process" foods are:
polishing off the bran (outer layer) of grains. The bran is filled with vitamins, minerals, and fiber - but it can add a tougher texture to foods
adding chemicals to change the food's appearance, flavor, texture & generally trying to make food more appealing (visually, mouth feel, or taste)
adding chemicals & other products to extend the food's shelf life (butter vs. partially hydrogenated oil, i.e.:trans-fat)
substituting cheaper versions of similar products to produce the same result (sugar vs. high fructose corn syrup)
Identify processed foods in the grocery store by reading the ingredient list. If the ingredient list is either longer than a 1/2 inch, or has ingredients listed that you have no idea (how to pronounce or) what they are, it is a processed food.
One of the biggest changes that I see my clients make in their health is by switching to better quality foods, or raw food ingredients. By simply making this change, and not changing anything else about diet (portions), your body will start shedding weight, and you'll start feeling better.