Lyle discussing the various dieting approaches
JUST READ THE FIRST TEN PARAGRAGHS or more if you want..
Here's the thing: all hypocaloric diets cause fat loss. And, for the most part, once you meet some basic requirements (mainly protein and essential fatty acids, without generating too massive of a deficit), the differences in fat loss are pretty minor and even more highly variable. Some folks appear to do better on keto diets (although I suspect that's the carb-load more than anything) but some do better with moderate carbs. Even there the differences are minor. Folks were reporting *maybe* 3 lbs extra fat loss over 12 weeks for CKD vs a Zone type of diet. Others reported better fat loss on the Zone type of diet. These were lean folks who were meticulous about counting their calories.
As far as I'm concerned it becomes a case of food/appetite/calorie control at that level (note: one exception is that women will tend to lose bodyfat better on lowered carbs, men might mobilize ab fat more effectively but that's debatable and highly variable). If a higher carb diet makes you hungrier and you eat more calories, you're going to lose less fat. Because you're eating more.
I've got a study here looking at wrestlers who were at 6% bodyfat. They were all on hypocaloric high-carb diets and they lost fat just fine. They were all on 12.7 cal/lb and 55-60% carbs. Yeah, they all lost some muscle but that's what happens at that bodyfat level, almost no matter what you do.
Seriously, as long as there's a caloric deficit, carbs don't magically prevent you from losing fat despite what many seem to think. Any 'magic' from a particular diet interpretation usually has to do with people spontaneously (or more easily) reducing calories and eating less. Which is fine, controlling hunger/etc. is crucial to diet success.
Even Duchaine, in one of his last Ironman columns commented on this. He mentioned that all of the goofier diets didn't seem to really give the expected benefits. It became more an issue of limiting diet breaker foods (typically carbs) at that point.
The reason being that most of what you lose (fat vs. muscle) is being controlled by internal determinants (leptin and all the hormones its controlling). So composition of the diet, beyond meeting protein and EFA requirements, and not creating too big of a deficit, tends to be fairly irrelevant outside of calorie/appetite control.
Even the simple "Eat less fat" is based on the presumption that if people follow that advice, they'll eat less total calories. Same with 'eat less carbs' (or more radically no carbs) or 'eat less sugar' (Sugarbusters) or the complicated food combining stuff. Whatever.
It's all a way to trick people into eating less without making them fixate on food (which causes psychological anxiety). Which isn't an inherently invalid concept, don't get me wrong. Of course, in reality we find out that while such approaches frequently do work for a while, people invariably compensate and end up eating about the same amount. But they have been so convinced by the diet book's spiel that calories don't count, that you can't get them to even count the calories at all. Atkins dieters are notorious for this: even if they haven't lost a pound in months, they will refuse to accept that they still have to monitor calories because of the line Atkins fed them.
One of the most staggeringly 'brilliant' comments I read one time in a review paper was to the effect of "While we don't know what the ideal diet for the treatment of obesity is, it will most likely contain adequate protein, sufficient dietary fat, and emphasize fruits and vegetables."
Seriously, 3 decades and 10 billion dollars worth of nutritional research and they came up with what my grandmother knew 50 years ago. I mean duh.
The bigger problem is arguably this: getting people to follow whatever dietary and/or exercise changes they make. Frankly, the issue of how to lose weight is trivial. The issue of how to get people to maintain their behaviors in the long-term is not. Obesity treatment research HAS to get away from the focus on this or that diet or macronutrient. It needs to focus on the behavioral stuff, getting people to change their habits for long enough to break old patterns.
Of course, statistically, most people fail at any behavior change they attempt. Stopping smoking, alcohol, whatever; the failure rate is generally pretty high. It's human nature: change begets anxiety and we don't like anxiety. It's usually easier to go back to old habits then to develop new ones.
As well, there is a psychological aspect of 'goofy' diets that appeals to many (it used to appeal to me). Basically, in order to stay on the diet they have to really, really believe in it. That means being fed a really good line of hooey by the diet book author. Zone dieters are generally *convinced* that the reason they're losing fat is because they are IN THE ZONE. Try to point out that they're losing fat because they are on a severely calorie restricted diet that is adequate in protein and fat - and they'll have none of it. Basically they have to believe in the diet to follow it long-term. Again, not a real problem except when the line of hooey that the diet book author is feeding people is such crap that it gets them into problems.
You'll note that most diet books are mainly an attempt to 'sell' the reader on the approach to tie into this psychological aspect of it all. Chapter upon chapter of why that particular diet is superior. This typically includes crapping on the mainstream dieting establishment, crapping on all other diets that are out there, and making up some reasonable sounding science to support whatever diet is being pushed. Because most diets can be summed up in about 3 pages but that doesn't sell books. The rest of the book is food lists and meal plans which makes it easy for the average person to follow it. But most of it is simply to convince the reader why the diet is superior and/or valid because that makes people more likely to stick with it.
Yeah, seriously, don't get me wrong. There may still very well be advantages to lowcarb diets over other diets (although even that is highly individual) even if increased fat loss at the same calorie level isn't one of them.
If nothing else, they do help to ensure adequate protein intake. A mistake that many make on high-carb diets (and one I have made) is eating too dang many carbs, which means that protein and fat (and EFA's) get shorted. Personally, I think a 75% carb diet is horribly imbalanced. I ate such a diet in college (didn't know any better and listened to my professors, which was a mistake).
You simply can't get enough protein or EFA's (or you can get one but not the other) when carbs make up that much of your diet. But I have routinely seen people eating like that (female clients would frequently be eating like 80% carbs, 10% protein and 10% fat). People tend to get and stay absurdly hungry on such diets as well which doesn't help with compliance in the long-term. Nor does it help with controlling total calories.
I don't even think that the 60/30/10 diet that Dan presented in Bodyopus is particularly balanced. Fat is too low. Yeah, he did actually state that fat would be 18% when you figured in EFA's but it's still on the low side IMO.
However, if you were to move someone from 75%/whatever to 50% carbs, 25% protein (or 1 g/lb) and 25% fat, I suspect that that would make a HUGE difference. Not because you're reducing carbs per se, but rather because you're finally able to get sufficient protein and fats (and can get enough EFA's).
I really suspect that's why so many people do report what appear to be magic results when they move to Zone or lowcarb types of diets. They tended to have been following crappy diets to begin with (too high in carbs and/or too low in protein; usually the latter) and just about any change would have been an improvement. Keto and Zone diets force people to get sufficient protein and fatty acids (and hopefully EFA's). They are superior to a 75% carb diet for that reason alone.
They also control hunger better. Meaning better compliance and calorie control. Both of which are crucial aspects of a diet. In that sense (hunger/calorie control), lowered carbs may very well be considered to have a 'metabolic advantage'. And one that makes such diets very beneficial from a fat/weight loss standpoint.
But in terms of causing significantly greater fat loss/less muscle loss at a given calorie level, the data just doesn't seem to be there. Not in the research, not in the real world. Not assuming the person is getting enough protein and EFA's in the first place. Basically, that's the issue in a lot of studies. Take someone with a crap diet (usually too little protein) to begin with, and a keto diet will be superior. Ketosis is VERY protein sparing if your protein intake is inadequate to begin with (many studies give 50 grams of protein or so while dieting). Assuming protein intake is adequate to begin with (at least 150g/day or 0.9g/lbs of bodyweight), ketosis doesn't appear to have much of an impact.
And don't get me wrong, I really wanted it to be true, I really wanted such diets to cause greater fat loss and spare muscle better. I really did. This is just one of those cases where I don't think the research/real world results support the idea that they do.
Now, some people do seem to benefit further (again, mainly calorie control/hunger) from reducing carbs even further (to 40% or 20% or even lower). Or even eliminating starches completely (this may help to break various food preferences/psychological carb addiction issues). Usually it's folks who are severely insulin resistant (generally very overfat, inactive, and were consuming the crappy modern diet to begin with). They can have a horrible time controlling appetite/hunger with even the smallest amounts of carbs in their diet because they have such severe rebound hypoglycemia, which tends to promote hunger. Removing carbs (starches, not vegetables) completely may be the only practical way to control hunger and reduce calories. Which is fine too.
