Invariably, every time I say that weight is a product of energy balance (ie, calories in vs. calories out) I get at least one person arguing ‘calories don’t matter! different kinds of calories affect the body differently!’.
I can’t really blame people for the confusion. There are a shit ton of diet gurus out there muddying up the waters with claims that combining foods ‘properly’ or cutting out certain foods or macronutrient groups is really the key to weight loss and that all you have to do is eat the ‘right’ foods and you’ll be able to eat all you want and still lose weight. Oh, and conveniently they just happen to be selling a list of those approved foods. Calories DON’T matter they claim, it’s the KIND of calories you eat that matters. “Those people who tell you to just eat less have got it all wrong” they say. “‘They’ have been misleading you, I’m telling you the TRUTH.”
All that black and white thinking has got people believing a false dilemma: It’s EITHER ‘calories in vs. calories out‘ OR ‘the kind of calories you eat‘ that matters! It’s a big ole’ moneymaker. They tell you they have the secret diet that will allow you to eat all you want and still lose weight, and you open up your wallet and buy it.
Here’s the truth, and I’m not going to charge you for it: weight is a product of energy balance, AND the kinds of calories you eat.
Lets start with the basic equation X +/- Y = Z, where X is calories in, Y is calories out and Z is total weight. The KINDS of calories you choose can affect the values of X and Y (Y moreso than X), but here’s where the diet gurus are misleading you: changing the values of X and Y doesn’t change the basic equation.
Some foods cause your body to burn more calories than others. Protein and fiber rich foods require your body to do more work to digest. It’s called the ‘Thermic Effect of Food‘. Eating foods with a high thermic effect makes your body burn more calories (Y), sometimes a LOT more calories. That’s why the list of approved foods your guru sells you will be comprised primarily of protein-rich foods and fiber-rich vegetables. Both are highly thermic. There’s also some evidence that whole, minimally processed foods are more highly thermic than equivalent processed foods (Y). Eating good quality nutritious foods can increase your energy level, which can lead to more spontaneous activity, which leads to a higher calorie expenditure (Y). Eating highly satiating foods can also cause a spontaneous reduction in total calorie intake (X). Protein and fiber, again, are highly satiating. As our understanding of the ways food affects our bodies grows, I suspect we will discover other ways that the kind of calories we choose can change the values of X and Y.
Eating a rich and varied diet full of whole, protein- and fiber-rich foods can absolutely change the way your body functions! In the end, however, it is still subject to the laws of thermodynamics. In an energy surplus it will store that surplus as mass (either muscle or fat depending on your activity level), and in an energy deficit it will burn stored energy reserves to fuel activity. Your task is to eat (and move) in a way that increases your energy expenditure to a level that exceeds your energy intake, if weight loss is your goal. Eating less isn’t the whole story, and sometimes eating MORE will produce a higher Y variable and weight loss will ensue, but optimizing your individual X and Y variables IS the way to get the Z you desire.
**A note to the nutrition nerds: yes, I’ve simplified things. That’s what I do here on my blog. This post isn’t for you, it’s for non-nutrition-nerds who don’t want to spend all their free time reading diet blogs and scientific abstracts.**