Calories = calories is all you need to know.

Unless

* You care about your productivity or health, in which case getting sufficient balanced nutrition is important.

* You care about body composition eg going on a diet is liable to lose you large quantities of lean body mass which sets you up for rebound weight gain down the track.

* You are one of those rare people who are affected by hunger. If you are one of those people you might want to consider the effect of diet composition, adequacy and timing on your appetite.

I also note: sample of one. Duration: 2 months (of people who lose weight over a 2 month period only a small fraction keep it off). Statistical significance: 0.

Couldn't have said it better myself! Jade Teta has a fantastic article on this — http://www.t-nation.com/diet-fat-loss/a-calorie-is-sometimes... — including so-called HEC (hunger, energy, cravings)

There's been work and research that state gaining weight is not a simple matter of calorie in = calorie out.

Gary Taubes has written a lot about it.

The thing is, how many calories does a piece of food contain? What is says on the packet? Probably not. Second is, how much calories do you burn? The same amount as the watts you generated on the circuit machine? Probably not.

And of those calories you got in, how many left through the waste canal?

Obviously it is a question of calories in = calories out, the question is whether what we are measuring is even close to either side of that equation.

At some level though, it HAS to be a simple matter of calories in vs. calories out. I will bet a large sum of money that if you literally give an obese person ONLY water and necessary vitamins for 3 months that they'll lose weight. You'll never find somebody who hasn't eaten anything for a month and is maintaining their weight.

Sure it's an extreme case, meant only as a thought experiment, but it's obvious that 0 calories in and non-zero calories out absolutely MUST mean weight loss. What are the alternatives?

Here's the thing... I'm willing to change my mind. Totally willing. Here's what it will take: Show me a person who is overweight and goes on a VERY strict, almost laboratory controlled diet for 6 months. Everything strictly regimented and monitored. If that person simply cannot lose weight then fine, Gary Taubes wins.

> Sure it's an extreme case, meant only as a thought experiment, but it's obvious that 0 calories in and non-zero calories out absolutely MUST mean weight loss. What are the alternatives?

Conversion of body weight to a form that has less stored energy per unit of weight mass (e.g., fat to muscle). That's unlikely with zero calorie intake (since activity, which is difficult to maintain with a too-extreme deficit, and protein are both important to it), but it balances the calorie equation just as well as weight loss does.

More generally on the point under discussion, adjusting caloric intake alone without changing calorie output is expected to produce weight loss if a bunch of other factors are held constant, but the way humans are constructed, its actually not at all simple to adjust calorie intake and not alter calorie output or any of the other relevant factors -- in fact, many of them the body will itself change as a result of a change in calorie input.

You're right, but that's not what it's about. Try putting yourself on a strictly regimented, hypo-caloric, laboratory controlled diet for more than a few days. It will consume all the willpower you have and then some.

The point is that enough sleep and exercise, the right mix of gut bacteria, and a diet consisting of sufficient protein, fat, and fiber, with very little simple sugars and starches, will allow you to feel satiated on fewer calories, and lose weight without having to count calories, strictly regiment your diet, or suffer through hunger pangs.

> Try putting yourself on a strictly regimented, hypo-caloric, laboratory controlled diet for more than a few days. It will consume all the willpower you have and then some.

I don't disagree at all. I just think the conversation shouldn't be about "is it calories in vs. calories out?!" and more about "What can we do to make it easier for people to eat the right amount or run a calorie deficit?" Could we massively tax bad food and subsidize good food? Attempt to change culture? Figure out the underlying neurological issues involved in overeating and attempt to create a targeted treatment to ease these issues?

I guess I feel like a lot of people try to obfuscate the issue by saying "It's more complicated than just calories-in vs. calories-out" almost as a way of absolving themselves from responsibility. Because, yes, running a calorie deficit for a long time is HARD. Like, I have a friend who's convinced "it's just a thyroid issue I have, calories-in vs. calories-out doesn't matter". However if there were a magic pill that caused them to only ever want to eat at most 1500 calories per day and start loving the taste of vegetables more than anything with no side effects I guarantee you that suddenly they'd be losing weight.

Whilst that's true, you really shouldn't use that as the argument - the point being made is that your body's ability to use a calorie in one type of food is different to your body's ability to use a calorie in another type of food.

A calorie = a calorie, but accessing it, sorting it, and storing it, depends on the package it comes in.

calorie in/out is true, BUT we have no way to measure what we put in and out. That's the problem with most peoples simple assumptions "you have eaten so and so many calorie, therefore .." - it is completely unimportant what you eat. It is important what is usable by your body. And there the "calorie in != calorie out?" research starts ..

I agree. I'm demonstrating how saying that calories in = calories out is both absolutely true and completely meaningless.

This is untrue, it IS that simple. When we talk about fat gain or loss, of course. Cutting out carbohydrates will make you lose glycogen, which contains mostly water (4 parts water, 1 part glucose).

It's very easy to lose water weight and say you lost more than you were supposed to lose because you're using weight as a measurement. If you use the amount of fat you have on your body, a low carb diet is no more effective than a low calorie diet at losing weight given the same amount of caloric expenditure.

Sorry but this is complete bullshit. I don't do Atkins any more. I can lose weight other ways more easily now. But when I did, twice many years ago in my twenties and my thirties, there's no way I could lose 20 kg of just water. It was very obviously fat. Anyone could see and touch.

I don't know where this absurdity of water losing came from, but It's utterly ridiculous.

Taking laxatives in large quantities (as some misguided young people do) does indeed reduce water mass significantly, besides screwing up one's digestive system.

That may be where the confusion comes from.

It's about 5kg of water loss that will mess up your statistics if you just measure weight. So if you are looking at weight, a low carb diet loses you more weight. If you look at fat, it performs the same as a medium or high carb diet.

That doesn't mean you can't lose fat on a low carb diet, of course.

Except I would have been unable to do low calories at the time because I felt it like starving, while low carbs was pleasant, sustainable (last time for two years) and worked like a charm.

So if I lost 5 kg of water and "only" 15 kg of fat, so be it... as opposed to 0 kg of anything with low calories.

In 30 years I've read a lot against low-carbs, but nothing that can reconcile the fact that it works.

Low carbs did make you eat lower calories, so if it works for you, that's great. A low calorie diet is not opposed to a low carb diet, a low carb diet is usually a low calorie diet.