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Why do low-carb diets work?


They do work, I know. But why? Why is 2500 kcal of fat and protein more efficent than 2500 kcal of carbs and protein (beside possible changes in testolevels and such)? If the energy out and energy in remains the same, why does it matter? Is it the ratio of fat versus lbm of the weight loss which is superior in low carb diets?

Btw, Im not adressing keto-diets here.


Insulin management




Ketones only yield 7 calories per gram instead of the 9 per gram that fat grams yield, so it is inefficient to use them for energy.


Heres the summary of what I learning in exercise phys. Carbohydrates are easily stored and if not used are easily stored as fat. Think of your glycogen stores(muscle energy) as storage sights for cho's. When these are full, the remaining CHO's go to storage (fat). When glycogen stores are depleted (low carbo diets) fat is the ultimate source for energy. Another thing to mention is that fat and especially protein required more energy to break down in the G.I. trac and initial stomach digestion. Without Carbo's you are basically getting all you energy form one fuel source (fat and a little muscle). The little muscle you will lose on this type of dieting will be the result of protein-neogenesis (the break down of amino acids into glucose). This typically happens during intense endurance training (marathon) and the low carb diet. Just remember, even if you do try this technique consume carbs post workout to shuttle nutrients/protein to your muscles (ex. Surge). I hope this helps a little. It's been a while since class!


read John Berardi's work on this site.


Low carb diets are less efficient! That's why they're so good.



umm, how 'bout b/c low carb diets generally cause people to be less hungry (not always) allowing you to eat less, and lose fat. And the initial water and glycogen loss contributes a few lbs. as well.


and protein-neogenesis? U just make that up??

It's gluconeogenesis which is the converting other energy substrates, amino acids and fats, into glucose.


Your body stores excess carbs as fat. If you have no carbs to use for energy it uses the stored carbs which are now fat for energy, thus you burn fat.


uhh.. I think the basic reason is because people get less hungry on low carb/keto based diets.

even in the absence of insulin we store fat just fine. according to lyle mcdonald, chlyomicrons stimulate ffa uptake and triglyceride synthesis into fat cells all by themselves, even in the absence of insulin.

gaining or losing fat, unfortunately, will depend on 24 hour fat balance.


Appetite is easier to control when insulin levels are properly managed.


Low-carb diets diminish appetite. Also, in the absence of dietary carbohydrate, more fat is used for energy. With ample protein this means less muscle loss on a diet and more fat loss.


Low carb diets work....but the search engine works better.


I don't get people saying that low carb diets curb your appetite and allow you to eat less. It's almost as if you guys/gals are claiming a calorie is a calorie.

I guess it's true that dietary fat provides satiety, but I'm pretty sure that fiber does the same (and I'm ASSuming that it's much easier to get fiber on a high carb diet due to the fact that you can eat grains, fruits, etc.) Eating a lot of fatty food is hard to do, so I can see how someone would lose appetite with that kind of diet at higher calorie levels (ie. Anabolic Diet,) but not at below maintenance levels. Besides, p+f meals seem to be a lot more calorie dense than p+c meals, so I'd think it would be hard to eat less than you could on a high carb diet.

I'm no expert by any stretch, but I have read most of the Berardi articles, Atkins books, and some other miscelleneous stuff related to low carb, or should I say 'carb-controlled' dieting. The whole premise of all of these is that a calorie is NOT a calorie. They all state something to the effect of 'you'd be surprised at how much food you can eat and still lose bodyfat.'

Me personally, I never had ANY luck with high carb, low fat diets. Now, I eat far more than I had (corrected for lean mass gains) and I lose bodyfat while retaining muscle - which I'm ASSuming is because I can eat more food (p and f) than I could while following the mainstream high carb diet.

I guess I'm confused that so many people would respond with 'you eat less with a low carb diet.' Fatty meals are more calorie dense and studies show that a calorie is not a calorie.


i wish my body would go into a state of protein neogenisis, sounds like a good deal, free protein hahaha


Also, I remember hearing that P+F


i haven't found that you can magically eat a lot more calories while on a ketogenic type diet and not gain fat. i've tested it myself and the fat gain (analyzed using hydro dunking) was the same as when i ate a balanced diet of 40/30/30.

and i also haven't found that FAT loss is any faster on a keto type diet than a non keto diet. sure, WEIGHT loss was faster because of water weight lost, but other than that I saw no benefit in terms of fat loss, when comparing identical calorie intakes (again, analyzed with dunking, no tantia scales or anything else)

maybe i just haven't seen it, but i have yet to find any magical benefit that ketosis/low carbs has over a diet that's balanced like 40/30/30 p/c/f, or 30/40/30, whatever. of course it has benefits over some idiotic macronutrient ratio liks 70%+ carbs, but that's a bad comparison

so what am i missing?


john, it may come back to carb senitivity.
Those that are insulin resistant are going to get differing results to those that are not, when maniulating the carb intake.


after years of terribly bad macronutrient ratio eating i highly doubt i'm doing great insulin wise