Top low calorie foods
Today I want to touch upon the myth that is “Negative calorie foods”. The whole concept driving this claim is that you burn more kcals from digesting a certain food than the actual kcal within the food itself. This is also referred to as diet induced thermogensisis (DIT) which is defined as the increase in energy expenditure above basal fasting level divided by the energy content of the food ingested & commonly expressed as a percentage (Westerterp 2004).
Reported DIT values for separate macros are 0-3% for fat, 5-10% for carbs, 20-30% for protein (Acheson 1993) thus if we take the average % for each macronutrient (1.5% for fat, 7.5% carbs & 25% protein) we can clearly work out that there are in fact no “negative calorie foods”.
Example, celery, the most commonly claimed “negative calorie” food. 100g celery = ~17kcal, 3g carbs (12kcal), 0.7g protein (2.8kcal) & 0.2g fat (1.8kcal). Therefore, given DIT for the specific macros above, eat 17kcal of celery & you end up with a NET 13.763kcal. Equation used = 12(0.25) + 2.8(0.075) + 1.8(0.015) = 3.237kcal burned from DIT of that 17kcal.
Not exactly negative is it? While I know I’m being extremely picky & that, in the grand scheme of things, 13kcal from celery should NOT be stressed out on, weighed or tracked, it’s the concept I want to get through to you. 13kcal is not negative 13kcal. Eat 3000 “NET” kcal of celery with a maintenance of 2500kcal & you will still gain weight (Hill et al 2012). Furthermore, take celery again as the example. What do people, especially a typical “mindless dieter”, do when they hear the claim that celery is “negative calories”? Start snacking on celery on its own or start snacking on it with peanut butter & Nutella which contain hundreds of kcals? The latter most likely. Another example “spinach is negative kcals so let’s add it to my pizza” you get the point. When you ingest something other than water or any artificially modified kcal free products, there will always be energy (calories) in it. Some will have lots (icecream), some will have barely any & be negligible in the grand scheme of things!