Calories are the only determinant as to whether you gain or lose weight. It's thermodynamics. 3500 calories deficit or surplus is approximately equal to 1 lb of body weight lost or gained.

Your body burns X calories per day to feed itself. If you eat less than this number, you will lose weight. Period. If you eat more than this number, you will gain weight. Period. Your TDEE or Total Daily Energy Expenditure can be easily estimated if your are so inclined, but it isn't necessary. Want to lose weight? Start at 2,000 calories per day. Monitor your weight across 4 weeks. If you aren't losing at a rate you're happy with, drop it to 1,800 calories per day. Repeat.

If you want to lose 5 lbs, you need a net deficit over time of 3500 * 5 = 17,500 calories.

Good/bad foods play a different role in your overall health, for example by impacting your level of water retention or satiety.

The major catch there is that, if some common hypotheses hold, then where a calorie comes from has a direct affect on how your body burns it. The example commonly used is to say you need and consume 3500 calories to support your current level of activity. If you consume 600 that your body will only store, then your body will behave as though you still need an additional 600 to maintain your energy level. Likely leading to you being lethargic until you get additional food. (Which, as stipulated, you don't actually want/need to consume.)

I wish there were some way other than the impolite downvote to register just how miserable believing this broken logic made me for a decade.

Can you expand on that? Calories in/out has lost me a net 30 lbs.

The human body is not a bomb calorimeter. Simply cutting calories in (and running to try to increase calories out) reduced my energy and crushed my mood. My body compensated for lower input with lower output.

Cutting out sugar and grains, on the other hand, improved all of those things, and dropped 50 pounds off me despite actually cutting out the running as well. I never had to count anything; without the broken satiety mechanism, I'm not going to accidentally eat 20 oz of steak like you might accidentally eat a half a pound of spaghetti.

This is the point where you say "ok but that's just a trick to reduce your calories in," but that's entirely the point: calories in and out is descriptive, not prescriptive. Thermodynamics says that if I am losing weight I am consuming less energy than I am expending; it does not say that if I consume less energy that my expenditures will remain constant and fat will disappear.

I lost 44 lbs on a disassociated diet, which is now over and my weight is stable by abstaining from sugar, as otherwise I only try to eat healthy, but I do not count calories or whatever.

Congratulations on your 30 lbs loss. Unfortunately not many people can abstain from eating. For some people it's a source of depression.

What works for you doesn't necessarily work for somebody else - and have you noticed how some people can eat whatever they want without getting fat? Freaking bastards.

>I lost 44 lbs on a disassociated diet, which is now over and my weight is stable by abstaining from sugar, as otherwise I only try to eat healthy, but I do not count calories or whatever.

It doesn't matter if you count it or not if you lost weight you were taking in less energy than you were expending.

>What works for you doesn't necessarily work for somebody else - and have you noticed how some people can eat whatever they want without getting fat? Freaking bastards.

Those people are a myth and it's been proven, they just consider "eating a lot" to be less than the amount needed to get them to gain weight. I mean I could eat 2000 calories of chocolate everyday and aside from the massive problems related to not getting enough vitamins/macros I'd still be losing weight.

Anyway congrats on the weight lost, we're all gunna make it bro.

Really? Then couldn't one subsist by just eating one or two bars of chocolate per day and some vitamin pills? Or maybe a liter of coke per day would work just as well? It would be a very cost efficient way of eating as both candy and vitamins are cheap around here (well, not vitamins but a bottle of pills last a long time).

I've always assumed that that wouldn't work which is why I'm skeptical to your "it's all about the calories" argument.

Sure. Here's the classic example: http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/...

Thanks! It's nice to be proven wrong sometimes.

Well chocolate doesn't actually have that much to it (a regular chocolate bar is only like 250 calories) so it'd have to be more than two bars a day.

The main problem (as I'm told) with eating nothing but pure calorie sources supplemented with...uh, supplements is that the cost of the supplements is very high. Remember you need protein, carbs(I guess these wouldn't be in short supply on the candy bar diet) and fats plus micronutrients too or your body will start to break and those supplements aren't cheap.

I do know people that subsist mostly on protein shakes, rice and various supplement pills when they are doing hard cuts for body building competitions and while it's stressful on your body you aren't going to die from it.

Agreed -- the method I explained was just calories in/out. The problem I had was that I didn't have enough data. The app and calorie counts on menus give me the data.

Diabetics have to manage insulin levels. They manage their carb intake because of this. It has nothing to do with managing their weight.

With respect to obesity you might consider what you just said: carbs are abundant and cheap. Therefore, people tend to eat a lot of them. Significantly more than they should. Carbs also do not tend to induce a level of lasting satiety that protein or fat does (note, 1g carb = 4kcal, 1g protein = 4kcal, 1g fat = 9kcal). So not only do people tend to eat a lot of carbs but they also tend to eat them more often because they don't feel full for very long.

Simple carbs will be converted to sugar quicker than complex carbs, and quicker than protein or fat.

But if you eat calories - in any form - that you don't need then you're going to store those calories.

And you're incorrect when you say that diabetics are only concerned with carbs. Diabetics cannot eat as much fat as they like, and are warned to eat a "healthy diet".

Not really. Obviously, preservation of energy must hold, but body weight isn't just a function of calorie intake because metabolism is regulated by hormones, which affect the rate of calorie burn and fat tissue formation. Human metabolism is far from being completely understood.

Shouldn't you expect to lose that water weight at some point though? Longer term weight gain should be calories in - calories out. What you eat might affect how full you feel (which could cause you to overeat in some circumstances), and macros matter if you're trying to build/maintain muscle.

My understanding is that peoples' weight problems are that they underestimate the calories of what they eat (related to specific foods or portions or forgetting details like the butter used for cooking) or overestimate that caloric effects of exercise.

Overeating may be the big problem, but abstinence from overeating is not really feasible for most people (it's depressing, really) and the truth is there are better ways of tackling overeating at the core. For me the interesting question is "why" we overeat.

For instance by eating healthier foods, instead of sugars and snacks filled with fats and refined carbs, you tend to feel less hungry. The theory behind it is proven actually, because sugars and refined carbs burn too fast, leaving you either with an empty stomach that wants more or with fat deposits from all the food that didn't burn at the same rate.

Water weight may make it harder to track your "true" weight, but that shouldn't affect your eating decisions.

More specifically, your water retention will fluctuate up and down within a narrow band depending on your diet, but you will never put on 40 pounds of water weight.

It's similar to limiting your how much water you drink so that you don't have all the liquid in your belly making you heavier.

Water retention is also a warning sign that something's wrong (like a hormone imbalance, one of the biggest causes for water retention) and you should probably take it easy. Fat people retain a lot of water. When people start a high-fat diet the first 5 pounds or so are from all the water loss (or even more).

> It's similar to limiting your how much water you drink

Not at all. In fact when dieting it's good to drink a lot of water, precisely to stop your body from retaining it. Odd, isn't it?

aside from hormone imbalances, why do you care at all about water retention?

You should be able to get a relatively accurate number by always measuring your weight first thing in the morning, before drinking anything. You have to be careful not to get fooled, this is some kind of "best possible scenario" because your body loses a lot of water through perspiration during the night, but it'll give you a somewhat solid baseline.

IMHO fats is too generic.

Do you mean unsaturated, polyunsaturated or saturated fats?

Margarine or butter?

The answer is just as significant for any diet as the carbohydrates quantity.