I have no idea what Sisson says in PB, but I haven't read on MDA or seen him say in any interviews I've watched/listened-to where he claims fat consumption has no impact on body weight.

Gary Taubes, on the other hand, has said it point blank: (for context start ~6:45)

"you can't eat carbs, you can basically exercise as much gluttony as you want as long you're eating fat and protein"

Carbs are fattening, protein isn't fattening, fat isn't fattening.

He put the case forth in GCBC that carb was required to store fat in every one of his lectures through 4/10 made that case as well. If he actually read the texts he cites instead of cherry picking quotes, he would not have made such a bone-headed mistake .... over and (over)^n and over again. Why anyone believes his nonsense any more just astounds me. The science from his own references does not support his failed hypothesis ... and he knows it, or should.

This is definitely not true, and I'm pretty sure they both acknowledge that in the end calories still matter. They believe it's much harder when limiting carb intake, or that there is some "metabolic advantage" to going low carb.

There is no magic in weight loss. Wanna lose weight? You need to be in caloric deficit. Sounds simple, but for most just too hard. What paleo/primal offer is a diet that does this without you even noticing via a few methods:

• the fact that you are avoiding a class of macronutrient
• food reward (you are avoiding hyperpalatable food that for many are easy to overconsume)
• its get you to start working out
• improves your sleep
• helps you manage your stress
• you IF and dont actually eat for periods of time
• eating whole real food, its just much harder to get the same amount of calories as eating donuts, bagels, desserts disguised as coffee, pizza, cake, ... you get the idea. Try overeating sweet potatoes.. now try that with pringles, bet you can't eat just one :)

There's probably even a few more I left out, hopefully you get the idea.

That's as wacky as the notion claimed by some unnamed practitioners of low-fat raw vegan who say you can eat as many carbs as you want and not gain weight. If anything, it's most accurate to say you can eat as much protein and consume as much alcohol as you want and not gain weight since those are the items most difficult for your body to turn into fat. But either way, yeah, calories matter. Gluconeogenesis doesn't just eat up all the calories you consume and turn them into magical invisible unicorn vapor.

I think the assumption is that you CANT eat so much more than your energy needs for any substantial amount of time if you're eating low carb. Your hunger hormones won't let you unless you're metabolically damaged.

Maybe you can do that for a week, but it gets pretty darn hard to do for a long time.

I often log meals into myfitnesspal app to get an idea where I'm at on macronutrient ratios (I'm weird and think it's fun sometimes). I eat on average about 60-70% fat, 20% protein, and 15% or so carbs (gonna try and go lower carb over the summer). I have an EXTREMELY hard time going much over 1500 or so calories, and I don't feel that I'm not eating a lot of food, I think I eat quite a bit. I think eating lower carb, and filling in those calories with fat and protein pretty much means you are taking in less calories, but feeling more full and satisfied at the same time. If I have a bad week and go off paleo I consume way more calories but feel much less satisfied and hungry all the time.

Remember that weight loss and no gain weight is different to lean out! After i red the "3000 cal a day and no more gain" by Taubes i tried to stay very very low carb high in fat and protein, following the guidelines of Sisson and Wolf...and the result? Gain fat, no muscle...worst recovery ever from my crossfit and strength session. High fat doesn't work for me.

The idea is that in the long run, your body will regulate your energy input and expenditure if you're not eating carbs. So you will find it impossible to eat more than you burn, and you will naturally become more active if you eat a lot.

....don't forget that its not just carbs that raise insulin in healthy people

An insulin index of foods: the insulin demand generated by 1000-kJ portions of common foods (PDF)

"....postprandial insulin responses are not always proportional to blood glucose concentrations or to a meal's total carbohydrate content. Several insulinotropic factors are known to potentiate the stimulatory effect of glucose and mediate postprandial insulin secretion. These include fructose, certain amino acids and fatty acids, and gastrointestinal hormones such as gastric inhibitory peptide, glucagon, and cholecystokiin (25, 26). Thus, protein- and fat-rich foods may induce substantial insulin secretion despite producing relatively small blood glucose responses.
....."

(an exception being if you are an insulin-dependent diabetic)

There is evidence on both sides. For one, Type 1 diabetics who do VLCing use very low insulin. By definition, they produce zero or very little insulin endogenously. If they VLC, they have to inject very little insulin. Just about every T1 diabetic on a ketogenic diet is thin. When a T1 diabetic starts eating moderate amounts of carbs and must inject insulin, he will gain weight independent of the actual calories he's taking in. Italicized since it's anecdotal and I am not entirely sure about this myself. Supposedly, the weight gain for such a person is a function of the amount of insulin injected, not the amount of calories -- i.e., rapid weight gain if eating high-carb but low-calorie meals vs. low-carb meals with identical calories.

As I mentioned before, it's possible to see weight gain by eating fast foods that do not have any carbs -- i.e., pork rinds. These items have fat, salt, and spicy ingredients -- items which spark "food reward." I experienced weight gain myself eating these. However, if you're eating Paleo (nothing fried or with added salt and spices), you don't eat them, since junk foods are by definition man-made.

There are exceptions to both sides. Some people are making absolute statements here. To quote Matt Stone, if you are not yet confused by nutrition, you haven't looked at it long or hard enough. If you don't have any skin in the game, stay neutral, stay agnostic. You'll have to eat your words soon when new discoveries are made.

Hi, Actually yes I have tried eating unlimited fat. When I first read Gary Taubes book it went against everything I knew, but I needed to loose weight. I decided I would go on a super high fat ketogenic diet so I could find out if it didn't work ASAP. Part of the reason I did this was because there is research showing that ketogenic diets can reverse insulin resistance and diabetic nephropathy in mice.

During the first month of my diet I went out of my way to eat butter, cream, bacon sausages, ribs, steak, cheese, cream cheese, coconut oil, olive oil indeed anything high fat. On a daily basis I was probably eating at least 1.5x my recommended calorie intake and never went hungry, and never said no to food. However by the end of the month I had lost 8kg.

I should stress I was doing no exercise and had a very sedentary lifestyle. I know this point is contentious, but it shouldn't be, as anyone who is obese can easily test the hypothesis (as I did). Counting calories is just pointless.

If you attempt to eat pure, unlimited fats, you'll run into a very potent rate limiting factor: bile salts. Once your gall bladder is exhausted, you'll experience a not so pleasant reaction: explosive diarrhea. (This most commonly happens to new paleo folks who have heard about coconut oil's benefits for the first time and try to eat lots of it at once before they're used to it.)

So in that sense, since your body will, um, forcibly remove it from your digestive tract, it becomes impossible to eat it in unlimited amounts, therefore you won't be able to absorb it all, therefore you won't be able to build fat from it.

The real question then becomes what's the rate at which you do absorb it, vs burn it off, so you can answer the question of whether it would cause you to gain fat or lose fat. If you absorb far less than you burn off, you'll obviously burn your already stored fat, otherwise, you'll still gain fat.

But it's a ridiculous way to "eat unlimited" anything, and would have serious consequences - it would be like the reverse version of binge/purge.

Even if you were to eat unlimited protein, you wouldn't be able to digest it all, and you'd wind up in rhabdo/rabbit fever. If you were to try and eat unlimited carbs, at some point you'd also not be able to digest it all, and a lot of it would be excreted.

You'd also wind up malnourished due to a lack of micronutrients, and also depending on what you pick, you'd be missing out on either essential fats, or essential amino acids if you do that long term.

Obviously no one will eat pure fat, or pure protein, or pure carbs. Doing so is insane and has bad consequences, but theoretically, there are going to be rate limits to their absorption.

The consequence of eating unlimited carbs was, for me, high blood sugar and A1C. My tolerance for carbs is high but I now know the limits for that macronutrient. Having seen that damage I'm reluctant to perform the same experiment with fats. In the sense of eating an ancestral diet I don't see any point in mass consumption either.

If I want to keep my calories up, I have to eat more carbs. If I don't eat the carbs my total calories drop. Taubes, Sisson- hell every gym rat trying to gain muscle mass knows this.

Dave Asprey actually claims to have kept his weight stable while eating something like 4000 calories a day- in the high fat direction too, since he puts butter and MCT oil in his coffee.

Taubes goes very in depth into the sort of studies he thinks are needed. I suspect the reason he doesn't mention testing this particular notion is because it isn't meant in the way his detractors like to take it. If the average person shifts from SAD to high-fat low carb, that average person ends up eating fewer calories in total pretty quickly.

Creator of the "Optimal Diet" Jan Kwasniewski had clients who have consumed more than 10000 kcal a day and they lost a LOT of weight very fast (I'm not sure but it was something like 20kg of FAT in 30 days or similar...).

Optimal diet is a very low carbohydrate, low protein and very high fat diet. You can lose weight while overeating but carbs and protein must be low (you usually eat at least 2,5 g of fat per 1 kg body weight. Some active individuals eat at least 3,5 g of fat per 1kg BW). Lately I'm working out very hard so my calories are somewhere at 4000-6000 75-85% from fat.

Here you go: https://sites.google.com/site/themikelinks/figures/sample-food/sample-food.PNG. This is a sample meal from one day a while ago. I normally don't weigh or measure food, I just eat what I want, but I was curious what it was so I checked it out on fitday. It turns out to be 5,000 cals, 75% fat. This is has been a typical day for me for the last three years. I work out 10 minutes a day at a crossfitesqe strength program, so there's no way I'm burning it off by exercising. I have maintained 175-185 consistently for the last three years. I only go up or down on purpose depending on energy needs and I do that only by adding or removing carbs.