The Law
When thinking about diet and exercise, there’s really only one thing to be mindful of: the First Law of Thermodynamics.
The First Law of Thermodynamics tells us that energy changes forms, but can never be created or destroyed. This is the defining characteristic of all systems that use energy and do work; it is inevitable, inescapable and probably lots of other things starting with ‘i’. But it’s the only thing anyone needs to know, and everything else follows after that.
It is the case that for 99% of the population, counting calories is all the work you have to do if you’re concerned about your weight. Measure your food, measure your energy burn during the day, and you’ll see right away if you’re losing weight, gaining weight or maintaining equilibrium. Some people — very smart people, it’s worth noting — believe this isn’t true, for various reasons of biology or endocrinology, but they’re wrong. Or, at least, they’re less correct than they could be.
Let’s start with the equation form of the assertion:
ΔE = E(in) – E(out)
Where E(in) is all the food you’re eating, and E(out) is all the calories you’re burning.
If ΔE < 0, you’re losing weight. This is true. This is an inarguable fact. Why? Because of the First Law.
Because energy isn’t created or destroyed, only converted, it means any energy you lose through your normal day-to-day processes has to come from somewhere. E(out), ideally, would be a measured value; the number of calories you’re burning as a combination of normal respiration as well as all the exercise you’ve done. This value for E(out) can be estimated fairly accurately by various methods. If you belong to a gym or health club, they may be able to do this for you for free or a small fee. You can also try calculating your own Basal Metabolic Rate and using various other web-based resources to calculate how many calories you burn through exercise.
E(in), then, should be an easy enough value to calculate and monitor to ensure healthy weight maintenance of any kind.
It really isn’t, though. E(in) is difficult to measure. The numbers are on the package, but those values aren’t entirely accurate.
Calories are typically calculated using a device known as a calorimeter. You put food in, it burns it, and measures the energy released (in a variety of methods, depending on the calorimeter). All food, naturally, has a positive caloric value, according to devices like this. However, humans aren’t calorimeters. We don’t burn calories the same way. Digestion itself takes energy, and there are kinds of materials that we just can digest, irrespective of their actual caloric value. Food labelling attempts to take these things into consideration by excluding calories from the stuff that we can’t digest, but these are estimates, and are subject to a measure of inaccuracy.
The old saw about celery being negative calories because it takes more work to eat than it gives back to you is particularly apt (regardless of the veracity of the statement). Certain calories are more available to us than others. Food is not all created equal. This seems like a complicating factor, but it really isn’t. It makes things a lot easier to tailor your diet for what you want to do.
There are a lot of diets out there that claim to reduce weight, though almost all of them require significant jumping through hoops. However, almost all of them have one thing in common: the restriction of simple carbohydrates. All of them limit or remove the source of the most bio-available calories in our dietary repetoire. This serves two functions:
- It increases the delta between stated calories and actual calories. That is, when you eat a spoonful of sugar (to make the medicine go down) the number of calories on the package is going to be very close to the number of calories that you get. By removing these items, you’re guaranteed that all the foods you eat have a more significant buffer, which is going to give you a bit of an edge when it comes to losing weight.
- Carbohydrates break down into simple sugars and promote spikes in blood sugar. Blood sugar spikes are countered by the body releasing insulin, but the body usually overshoots a bit, just in case. This tends to make you crave more sugar, so you eat more, which means there’s more insulin, etc. You end up in a small feedback loop that can make you eat more than you originally intended.
Systems like the Zone or Paleo diets will claim to help you lose weight, even if you eat the same number of calories, but that’s really just a bit of sloppy marketing to get you to buy in. Again, humans aren’t calorimeters. Both Zone and Paleo encourage eating things that aren’t very calorie dense and have a lot of extra roughage that fill you up. Five-hundred calories worth of celery isn’t any different from five-hundred calories of potato chips on paper, but almost no calories actually make it into your system if you’re eating all that celery, whereas almost ALL the calories in the chips go straight to your ass. (Incidentally, 500 calories of celery is approximately 5.5 kg worth of the stuff.)
The Atkins diet, for all its vilification, wasn’t as meat and fat centric as it appeared, though it was still of dubious health value for people who weren’t dangerously overweight. The diet tried to leverage an important property of fat — it makes us feel full — as well as so drastically reducing carbohydrate based calories that the body would be tricked into thinking it was starving. This state — ketosis – is something the body does when it doesn’t have enough sugar calories to feed the brain. It switches over to burning fat as much as it can for energy, which is why people often saw rapid weight and fat loss while using Atkins. The diet was otherwise fraught with too many pitfalls for someone to reasonably consider without the supervision of a doctor, however, which is why it has badly fallen out of favour in the last few years.
(To be clear, the Paleo diet can also lead to ketosis if carbohydrates are sufficiently restricted. This does not seem to be a property of the Zone diet.)
In the end, anyone can construct a diet plan that has the desired effect on their weight. It’s more important to adjust for nutrients than specifically exclude or include various types of food. If you’re mindful that not all foods relinquish their calories to you in the same way, you can adjust your intake accordingly. Increase the number of calories over what you burn for weight gain, and reduce the number of calories below what you burn for weight loss. If you’re still gaining weight when you want to be losing it, you simply haven’t accounted for something in the equation correctly. Either you’ve overestimated your burn, or underestimated your intake. If you don’t have any overriding medical issues, (e.g., thyroid problems), this will work for you, 100% of the time, guaranteed.
It’s the Law.
