"But Dr. Jeffrey Friedman, an obesity researcher at Rockefeller University, argues that contrary to popular opinion, NATIONAL DATA DO NOT SHOW AMERICANS GROWING
>>>>UNIFORMLY<<<<< FATTER.
Instead, he says, the statistics demonstrate clearly that while THE VERY FAT ARE GETTING FATTER, THINNER PEOPLE HAVE REMAINED PRETTY MUCH THE SAME."
He's saying that the explanation for the problem is not that a large proportion of USers are way fatter than they've ever been. (And btw, the UK and Australia have seen similar increases in the obesity rate.) What he's complaining about is the use of a _mean_ to suggest that everyone in the country is carrying around 6-10 lbs more than their counterparts in 1991. Rather, he's saying that the research is showing that most "normal" people weigh about the same or just slightly more. The big increase came from gains seen when comparing those at "mid-range" in 1991 to those at "mid-range" today, and when comparing the obese now and then:
Dr. Friedman points to careful statistical analyses of the changes in Americans' body weights from 1991 to today by Dr. Katherine Flegal of the National Center for Health Statistics. At the lower end of the weight distribution, nothing has changed, not even by a few pounds. AS YOU MOVE UP THE SCALE, A FEW ADDITIONAL POUNDS START TO SHOW UP, BUT EVEN AT MIDRANGE, PEOPLE TODAY ARE JUST 6 OR 7 POUNDS HEAVIER THAN THEY WERE IN 1991. ONLY WITH THE MASSIVELY OBESE, THE VERY TOP OF THE DISTRIBUTION, IS THERE A SUBSTANTIAL INCREASE IN WEIGHT, ABOUT 25 TO 30 POUNDS, DR. FLEGAL REPORTED.
as for genetics, he is talking about OBESE people so he is already talking about Deb's minority. he's saying that obese people have a genetic problem. It's NOT that they can't lose weight, it's that they fight GENETICS every step of the way when they try to maintain that loss.
FRiedman is also talking about what is popularly known as a "set point" weight. It's much more complicated than what you read about in Men's Health or Women's day, but if you want the beginnings of a better understanding, I'd suggest picking Lyle McDonald's brain. <www.bodyrecomposition.com>. I follow him because I'm into weight lifting and he knows the research on this backward and forward because he helps wacko lifters get down to insanely low body fat levels.
As he explains it, some people are just genetically predisposed to easily gain weight and have a hard time taking it off. Make no mistake: he's not "making excuses" for people. He could also give you a mini-dissertation on environmental factors that have contributed to the problem. Our genetic heritage, he would say, served us well under conditions of scarcity. It does not serve us well under conditions of plenty. We have bodies that horde energy and don't like to give it up. He's simply telling it like it is. His favorite expression is, "Your body hates you."
It's a no-brainer that sedentary lifestyles and poor eating habits have much to do with this, but the researcher is talking about _predispositions_ and factors that _shape_ the conditions under which one encounters that environment. And I'm not going to so readily dismiss genetics. I'm from a family with a predisposition to have a high cholesterol levels and most of the men die in their 40s. The high cholesterol problem is congenital and diet, exercise, and drugs have little to do with it. They just published a study on WWII vets, following them from the draft to current life, and these guys were showing high cholesterol levels at the age of 18-19. My son's gf, by no means fat, has high cholesterol, but it's a genetic problem not a problem re: poor eating and exercise habits.
If you're into it, Lyle's got a pretty cool regimen for people who want to get below "normal" bodyfat ranges. heh. The workouts will kick your ass in! i.e., if you don't puke after the depletion workout, you're probably not doing it right. Butch up, choad! :))
here's a bit on why and what leptin has to do with it:
<...> Lyle M: I'd say leptin may be one of, if not THE most important hormone when it comes to dieting and fat loss. I could literally talk about it all day but I'll spare you the pain.
To give you the quick course, leptin is a hormone released from fat cells which tell the brain, essentially, two things: how much bodyfat you have, and how much you're eating. Leptin basically 'tells' your brain what's going on with your fat and energy stores. When you overfeed, leptin goes up; when you diet, leptin plummets. It changes more slowly in response to real changes in bodyfat percentage. In response to this, your brain modulates various neurochemicals (such as Neuropeptide Y and corticotrophin releasing hormone, NPY and CRH) which further regulate other aspects of metabolism such as appetite, metabolic rate, testosterone, cortisol, GH, and a bunch of others.
That's on top of doing about a billion other things in the body. Leptin inhibits fat storage in fat cells, promotes glycogen storage in muscle (and increases fat oxidation in muscle), plays a role in immune system function, is involved in fetal development during pregnancy, can kill fat cells permanently, is probably involved in bone growth, and a whole bunch of other things.
I originally 'discovered' leptin while looking at something else, the issue of nutrient partitioning (where calories go when you eat them). For years, I've wanted to know why fat people lose less muscle when they diet than lean people. My idea was that 'If we can trick the body into thinking we're fatter than we really are, we can lose less muscle when we diet.' Maybe we can gain muscle more easily without putting on fat too.
So I went looking for major differences between fat and lean folks. You've got the obvious, bodyfat percentage. YOu see differences in insulin levels, differences in blood free fatty acid levels (which is part of the story, it gets harder to mobilize fat for fuel when you're lean, so your body uses muscle; it's also why ephedrine/caffeine and GH both increase fat loss and spare muscle) and a lot of other differences. But none really stood out.
In looking at the topic, I kept coming across references to differences in leptin levels. Now, I'm inherently fairly lazy, and I had ignored leptin (which was discovered in 1995) up until that point. It was just another hormone system that I didn't want to learn about, and I couldn't bring myself to care. That and the research was too fragmented to really draw any conclusions. By the time I started looking at the topic (in 2000), the picture had become much clearer about what leptin was, what controlled it and what it did. And the answer was that it controlled nearly everything and did almost as much. Especially in animals, but also in humans. In response to falling leptin, appetite goes up, metabolic rate crashes, hormones go to hell, fat storage increases. In response to increasing leptin (to a degree), appetite goes down, metabolic rate goes up, hormone levels increase, the body tries to put a brake on fat storage and pushes calories to muscle for burning. Leptin was the partitioning hormone we'd been looking for.
Wannabebig: So I take it you stumbled upon the Holy Grail of fat loss in a way.
Lyle M: I guess you could say that, suddenly a puzzle I'd been working on for nearly 10 years started to fall together. Why leaner folks lose more muscle than fatter folks, why you can gain muscle and lose fat as a beginner (actually, that only works for fat beginners), a whole bunch of other stuff too.
Now you may remember that researchers had tried injecting leptin into fat folks to cause weight loss. But it only worked a little bit at high doses. That's ultimately why everybody forgot about it as a drug, it didn't do what obesity researchers wanted it to do (make them a billion bucks by solving obesity). So they moved on. That would seem to sort of derail my enthusiasm and interest.
There were two problems though with this approach. The first is that fat folks already have tons of leptin. But their brains and other tissues aren't responding to it. They are leptin resistant (this is analogous to insulin resistance/type II diabetes where there's plenty of insulin but it doesn't work very well). Just jacking in more leptin wasn't going to solve the problem. Leptin didn't really cause weight loss in that respect anyhow. Research looking for ways to sidestep leptin resistance (or increase it) is still ongoing.
The bigger problem is that the researchers weren't using it correctly at all, but apparently nobody but me could see the problem. It's not that leptin per se is the problem or cause of obesity (or the reason diets fail). It's falling leptin during the diet (very low leptin, as seen in lean folks is a problem too but nobody really cared to inject lean folks with leptin, why bother). The researchers didn't need to be increasing leptin under normal conditions; they needed to be maintaining leptin during a diet. Of course, obesity researchers want drugs that work without diet or exercise because most people are lazy as shit so this idea didn't really scan.
See, during a diet, leptin drops much faster than bodyfat percentage. After 7 days on a diet, leptin may be down by 50% from normal. Of course, you haven't lost 50% of your bodyfat. After that, leptin will continue to go down along with bodyfat percentage. It's the drop in leptin that 'tells' your brain "Hey, we're starving, shut the system down." One researcher (in a 1998 paper) had made oblique reference to my idea that maintaining leptin levels on a diet might be more important. But nobody followed it up until a few months ago.
In the first study, on rats, they wanted to find out if dropping leptin was the reason that sibutramine (Meridia, a new diet drug) stopped working. So they gave rats either leptin alone, nothing, sibutramine, or sibutramine+leptin (just enough leptin to maintain levels at pre-weight loss levels). the nothing group lost nothing, neither did the leptin group. The sibutramine group lost weight and then plateaued (as metabolic rate and the rest adapted) and the sibutramine + leptin group just kept on losing weight with no plateau. But that's rats.
Finally, last month, someone tested the idea in humans. In that study, they injected low dose leptin into dieting individuals to restore normal leptin levels (i.e. at pre diet levels). And, no surprise to me, this corrected the drop in metabolic rate and thyroid (and caused more fat loss). This is how injectable leptin should be used: to maintain pre-diet levels and prevent the normal adaptations to dieting. I had realized this back in 2000, that falling leptin levels during a diet were the cause of the problem (and the very low levels of leptin seen in very lean folks were causing other problems). One researcher put it best 'Leptin exists as an anti-starvation hormone'; it works to keep you alive when you're starving to death (and dieting and starvation are fundamentally the same to your body).
So we (we at this point was myself and Elzi Volk) started looking for ways to raise leptin. Short of drug solutions, the easiest way is to overfeed for short periods of time (there are also nutrients like zinc, vitamin E and fish oils that play a role too).
Because, in the same way that leptin drops way faster than fat is lost, it rebounds way faster than fat is gained. So underfeed for a week and leptin drops by like 50%. Overfeed for a few days, and it rebounds by some percentage (depending on how much you overeat). The key is eating enough calories for long enough to rebound leptin (thus 'telling' your brain that it's ok, to normalize metabolism) without putting all, or hopefully any, of the fat back on. Of course, this is also helpful psychologically, prevents the real food binges from occurring, because the cheat days are now planned.
In one of the early leptin studies, this had actually sort of been demonstrated but the researchers were too dense to see what was going on. In that study, they dieted the hell out of a bunch of fat women for 4 weeks. Leptin and bodyfat both dropped. Then they refed them gradually for a week. Leptin came back up. But fat continued to be lost. To me, this was a profound observation, I don't recall the researchers even really noticing it (I may be wrong: this may have been the study where the one guy said 'maybe keeping leptin up on a diet is important', well, duh!). http://www.wannabebig.com/printarticle.php?articleid=87
(yeah, yeah, i know. what does this guy know. I urge you to go talk with him at his site. He's probably the most honest person I know when it comes to looking at the research.)
"We're in a fucking stagmire."
--Little Carmine, 'The Sopranos'