A CALORIE IS A CALORIE IS A MYTH?

MYTH BUSTERS Episode 1

For all the great content and information that is out there, there is also a lot that is often not based in fact. We have all seen it; the magic weight loss pills, eggs being bad for you, gluten being the devil, the list goes on. I find it disheartening to see people get influenced by this information and follow it just because some celeb or social media star posts it on their page.

My intent with these posts will be to look into the science, both good and bad behind some of these myths. Even with research one has to keep in mind that not all studies are created equal. Some reasons a study may be misleading: the authors are invested in a particular outcome, poor methodology, lack of control or comparison, etc. This unfortunately can make things even more confusing. You have seen it before, a news source throws up a eye catching head line with a huge claim, often times when you look into the actual study it is far from the claim or the conclusion is unclear.

So the first myth is “a calorie is a calorie”

Right off the bat, something seems odd here. So I can eat 2000 calories worth of ice cream or 2000 calories worth of protein and calorie wise they are the same?? Even those that practice flexible dieting, meaning the macro-nutrient ratio is the crucial portion of a diet know this is false. Now this makes sense to an extent, especially after you read the post in terms of having a certain amount of protein, fat and carbs. There is a relatively strong argument that even that is not quite right depending on your goal. If your goal is optimal health and function then there’s more to it than just a specific macro-nutrient ratio, but I digress and will leave that for another day so let’s get into the topic at hand.

Over and over we have heard that a “calorie is a calorie”. While on the surface this may be true, when we look closer we find out that science would strongly disagree.

Let’s cover a few reasons a calorie is NOT a calorie:

--The thermic effect of macro-nutrients (aka how much energy it takes to metabolize, convert these to energy, etc) and how many NET calories you get from a 100 calories of each:

Fat: 2-3% - 98 calories NET of 100 consumed

Carbs: 6-8%- 93 calories NET of 100 consumed

Protein: 25-30%- 70-75 calories NET of 100 consumed

This means that for a 100 calories consumed of each macro-nutrient you would have the least NET calories from protein meaning less excess calories post processing (1). This is why high protein diets have been shown to increase metabolism and suppress appetite (2,3).

--Different food have different satiety (the feeling of fullness post consumption). This means that eating 500 calories of ice cream vs 500 calories of broccoli will give different levels of fullness and thus the one leaving you feeling less full, despite same calories will increase the odds of over eating (4).

- Various macro-nutrients and foods have different glycemic loads. This means that different foods have different effects on blood sugar and insulin. Higher blood sugar spikes from higher glycemic foods such as simple carbohydrates will increase cravings once blood sugar crashes and higher release of insulin signals the body to store more fat (5).

So let’s take some sample diets and their NET calories(NET= calories consumed- calories used up):

1. A carbohydrate based diet: 2000 calories. 70% carbohydrates, 25% protein and 5% fat.

NET calories: 1765

2. A protein based diet: 2000 calories. 70% protein, 20% fat, 10% carbs. NET calories: 1600

So what does that mean? That means that the person who eats the first diet, assuming both have similar metabolism and activity levels/calories burned that the first one will have an excess of 1155 calories per week. So if they were two clones with the exact same lifestyle and routine and the protein person had a 0 NET caloric intake weekly, the person on the carb based diet would gain a 1lb of fat every 3 weeks while the other stayed the same. So by the end of the year, the carb based clone would be roughly 17lbs heavier while the other stayed the same.

So with that I would argue that on a day to day basis a calorie may be a calorie, but when you look long term in terms of excess calories and composition that a calorie is definitely not just a calorie, and one high on carbohydrates may require more activity in order to equal the NET calories of a protein rich diet.

Thanks for reading, Vitas

Jequier, E. “Pathways to obesity”. Int J Obes Relat Metab Disord. Spet 2002.
Johnston et al. “Postprandial thermogenesis is increased 100%....” J Am Coll Nutr. Feb 2002.
Veldhorst et al. “Presence or absence of carbohydrates and the proportion…” Br J Nutr. June 2010.
Holt et al. “A satiety index of common foods” Eur J Clin Nutr. Sept 1995.
Lennerz S. et al. “Effects of dietary glycemic index on brain…” Am J Clin Nutr. June 2013.

Images from physiqonomics.com

Check out their post on the topic: http://physiqonomics.com/calories-child-friendly-version/