[samuelbrin]

I wish I had data to back this up, but there is no chance I was in caloric deficit on the keto diet. I lost lots of weight at the time. Not claiming my body violated energy conservation, but clearly this is more complex than "you don't get weight loss for free so you have to exercise more". So many folks doing the keto diet are sucking down ungodly amounts of bacon, heavy cream, etc and losing weight

[ghshephard]

They are replacing even more ungodly amounts of calories in the form of carbohydrates with that bacon/cream. Honestly, you can only eat so much bacon before you get sick of it, and your body just screams "Yuck. Stop eating. I'm full".

That's not true of things like rice, noodles, bread, etc.. where for many people eat some, and your body is like, "Awesome. Bring it on" in a never ending cycle.

Put another way - Satiation happens a lot faster, and lasts longer, when you are eating protein/fats, than it does when you are eating refined carbohydrates.

I think that what made it clear to me, is that there are no metabolic chamber studies (where people's activity and diet are perfectly controlled) that have ever demonstrated significant variation from the calories in/calories out model. Carbs, Protein, Fats - doesn't seem to make a difference, your weight is simply a reflection of your metabolic output and caloric-intake.

Stephan Guyenet also has an interesting perspective here:

http://wholehealthsource.blogspot.sg/2011/08/carbohydrate-hy...

[samuelbrin]

I don't doubt for many that reduction in carbs amounts to reduction in calories. For others though, eating a lot, and not worrying about consequences, is a coping mechanism for how shitty the diet is. I'm super biased from my own past experience, but I was having 3000+ calorie days with minimal exercise and losing weight on keto. Open to the idea that I'm somehow wrong though :-)

[ghshephard]

They've tried all sorts of diets in metabolic chambers - and it's really quite amazing how closely the observed results track the predicted results. Determine a person's BMR, and then feed them a variety of diets higher, or lower, than that BMR, and watch their body mass (exc. water) increase, or decrease as expected.

Possibly the case that when you were eating carbs, you were putting away 3500 calories a day, and that dropped to 3000 calories a day when it was just meat? I know that just a casual stroll through the mall on a refeed day for me, I have zero difficulty putting away 6000+ calories - refined carbs are shockingly calorically dense.

Also - for some time on a Keto Diet, you are going to be dropping a ton of water - so the scale will be dropping like a rock, regardless of what your actual body weight is doing. Getting a DexaScan, or whatever lean/fat body mass assessment you prefer to see what's really going on.

[barney54]

The water loss is one thing I like about a low carb diet--you get positive feedback right away. It isn't real weight loss, but that doesn't matter. The point is to get started and feel like you have made progress in the right direction. Then the real, much slower, weight loss can begin.

[ghshephard]

Completely agree with you. And, even though I realize exactly what's happening, I also like it. You can even make the up/down swings work for you. The 4-hour body slow-carb approach has you "refeed/binge" once a week, where you usually put on 8-10 pounds in a single day. But because you know it's going to happen, it's not particularly worrisome, and then you get the bonus the next week of dropping 2-3 pounds on the scale every day.

But, I think it's also a good idea, in addition to enjoying that little bit of gamification on your scale numbers, to also have a good sense of what's actually happening in the body mechanics.

That way, you get the best of both worlds.