Is it true that raw steak has hundreds less usable calories than when it is cooked? Raw peanuts lead to more weight loss than roasted ones? Should I try eating only raw food to stay slimmer?
The calories obtained from a given food (or meal, or whole diet) vary due to several factors. Cooking is one of them, but there’s also a great deal of individual differences which mean you and neighbor could eat the exact same cheesesteak and not absorb the same amount of calories from it. Isn’t that fascinating?
This individuality in calorie absorption is due to differences in your gut microbe populations, your unique genetics (how much you make of certain enzymes) and even differences in chewing!
Processing in general increases calorie availability, not just cooking. Removing fiber allows your body easier access to the energy-yielding components of a food. Increasing the surface area of grains by grinding them into flour additionally allows your body to access more calories per gram. This effect is really pronounced with nuts and nut butters, with one study showing that 25-30% of the calories in whole almonds may be inaccessible to the body (depending on how thoroughly you chew them) and nut butters which are conveniently mechanically mashed up into smithereens give us more calories to use.
Does this mean you should drop all cooked and processed food from your diet right now, for an easier time controlling your weight? Not really. Here’s why:
3. Cooking makes food safer. You’re more at risk for foodborne illness if you eat all raw food, because cooking food kills bacteria that cause E. Coli and salmonella, among other nasty bugs. Next time you have food poisoning, I doubt you’ll feel it’s worth it to increase the odds you’ll ever go through this again, just to save a few calories.
But here’s the most convincing bit for me (since we’re talking brains, weight, and appetite control, which is my wheelhouse):
4. If you decrease the amount of calories you absorb the calories from food, say by switching from peanut butter to plain raw whole peanuts, your satiety signals will adjust accordingly. The satiety signals perceived by the brain (as reviewed in my book Lean Habits for Lifelong Weight Loss) operate though accurately sensing Calories Accessed, not Food Down The Piehole. Satisfaction signals arise during assimilation. That’s why chewing and spitting out food isn’t satisfying, nor is (forgive the graphic reminder) throwing up your food.
So back to the peanut butter example: If the lipase enzymes in your gut have limited access to the fat (and hence, calories) in the peanuts due to more interference from the natural structures, you won’t hydrolyze the triglyceride molecules. It’s the hydrolysis products of fat digestion which lead to endocannabinoid production, OEA circulation to the hypothalamus, and the development of satiety. Translation: You’ll get fewer calories, and you won’t be as full.
(And if you like peanut butter as much as I do, you’ll probably feel like you missed out, because peanut butter tastes 498% better than raw peanuts. Feeling deprived isn’t helpful for long term weight loss if you haven’t found that out already. If enjoying peanut butter with all it’s highly-bioavailable calories keeps Cob’s Bakery banana chocolate chip scones out of my mouth, I’m winning.
The bottom line:
Eat things you enjoy. Odds are, that’s a mix of some raw foods (crunchy salads, crisp apples, juicy summer peaches) and some cooked food (a perfect steak, pizza, omelets, grilled chicken, steaming hot chili). If it’s all the same to you, choose less processed foods where you can, but don’t worry if it’s cooked or raw.
Yet again, we see that going to dietary extremes, as with so many other examples, only means missing out on some important benefits. The shortest route to health and leanness: Mix it up, stay happy. Enjoy your food.