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Thermogenesis

Weird word, right? We might have titled the blog “thermic effect of food” or “specific dynamic action”  but I don’t think either would have helped. Let’s talk.

Starting at the beginning and briefly, the body burns calories in one of three ways:

  • basal calories to keep you alive
  • activity calories that allow you to move
  • diet-induced thermogenesis (DIT) or the calories it takes to ingest, digest and generally manage your food or diet internally

We estimate the calorie burn of DIT to average 10 percent/day above those basal calories.

Let’s use some real numbers. A 50 year old female, 5’4″, 140 lbs. has a basal metabolic rate of 1240 calories/day. Her DIT would add or use up another 124 calories/day. So, before any activity (like sitting up or putting on the coffee), survival will require that woman consume 1364 calories to make it until the next day. Assuming normal activity, her total requirement would be about 1600 calories/day.

The research supports that it matters WHEN those calories are consumed. A recent German study of normal weight individuals suggested a 2.5 times difference between concentrating the calories in the morning (breakfast) or concentrating them in the evening (dinner).

Results were published in The Journal of Clinical Endocrinology & Metabolism. Only men were studied which is a shortcoming of the research but it was a single-blind, randomized, crossover study which scientists like. (OK, we really like double blinded studies but when you ask someone to eat a meal, they can see if the meal is big or small, so it was the researchers who were “blinded” in the study.)

Researchers indicated the blood sugar control was better with the morning “concentration” of calories suggesting better overall metabolic health for the individual including less obesity. As always, we say more study is needed but this also seems like common sense.

Eat the calories when you’re going to use them to be well,

Marcia

 

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