Article in the Wall St Journal today made me feel sooo much better about my previous diet "failures". Waddya think?

I knew that there was a biological reason for how hard it is to keep weight off. I also believe that the more times you diet the quicker and stronger this response is. So obviously those of us who started dieting in 6th grade have an impossible task by the time we are 30. It's hard to defeat Mother Nature!

Can't Keep the Weight Off?

Maybe Leptin Is the Culprit

July 8, 2008; Page D1<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

So, you ate less and exercised more and lost weight. But now the pounds are piling back on. You're hungrier than ever, and you can't seem to resist food. Once again, it's all your fault, right?

Wrong. Blame evolution, and the fact that for the vast majority of human history, famine was a bigger threat than flab. Even your seeming lack of will power is part of a complex biological system that drives humans who have lost weight to regain it, according to new brain-scan research by scientists at <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:place w:st="on"><st1:PlaceName w:st="on">Columbia</st1:PlaceName> <st1:PlaceType w:st="on">University</st1:PlaceType> <st1:PlaceName w:st="on">Medical</st1:PlaceName> <st1:PlaceType w:st="on">Center</st1:PlaceType></st1:place>.

"Loosely put, after you've lost weight, you have more of an emotional response to food and less ability to control that response," says Michael Rosenbaum, lead author of the study in this month's Journal of Clinical Investigation.

The key driver of this system is leptin, a hormone secreted by fat cells. When humans (and rodents) lose 10% or more of their body weight, leptin falls rapidly and sets off a cascade of physiological changes that act to put weight back on. Skeletal muscles work more efficiently, thyroid and other hormones are reduced -- all so the body burns 15% to 20% fewer calories, enough to put back 25 pounds or more a year.

This mechanism kicks in whether people are obese or relatively lean before losing weight -- and researchers believe the effect can last for years. In previous studies, giving subjects replacement leptin reversed the metabolic changes, in effect tricking the body into ignoring the weight loss.

The latest study shows that these metabolic changes are mirrored in altered brain activity when people lose weight. The Columbia researchers put six obese subjects on liquid diets and reduced their weight by 10%, then gave them replacement leptin or a placebo. At each stage, researchers observed their brain activity using functional MRIs when they were shown food and non-food items.

The scans showed that in the weight-reduced state, the subjects had more blood flow in areas of the brain that govern emotional and sensory responses to food and less in areas involving control of food intake. When the subjects were given replacement leptin, brain activity returned to what it had been before they lost weight.

There are still many unknowns about how blood flow in the brain corresponds to behavior. "I can't look at these scans and say, in 30 seconds, you're going to eat a banana," says Rudolph Leibel, a co-author of the <st1:City w:st="on">Columbia</st1:City> study who helped discover leptin in the 1990s at <st1:place w:st="on"><st1:PlaceName w:st="on">Rockefeller</st1:PlaceName> <st1:PlaceType w:st="on">University</st1:PlaceType></st1:place>. Still, he says, the brain images provide further evidence of the powerful biological forces that send humans into survival mode, mentally and physically, when food is scarce and fat stores decline. "These people act as if they are hungrier, and combined with reduced energy expenditure, that's the 'perfect storm' for gaining weight."

Dr. Leibel also says that people should understand that regaining lost weight "is not free will. It's biologically determined and the species that didn't have this are the ones you see in the <st1:place w:st="on"><st1:PlaceType w:st="on">Museum</st1:PlaceType> of <st1:PlaceName w:st="on">Natural History</st1:PlaceName></st1:place>." It's only been in recent decades that this mechanism is contributing more to obesity than survival. "Now, anyone can summon an unlimited amount of food just with a cellphone," he says.

Scientists originally thought leptin might be harnessed as a weight-loss drug. Amylin Pharmaceuticals Inc. continues to research that possibility and is in Phase 2 trials of a combination of leptin and pramlintide, a diabetes drug. But leptin may hold more promise in helping to keep weight off, an area that the <st1:City w:st="on"><st1:place w:st="on">Columbia</st1:place></st1:City> researchers say deserves more attention.

How do some people manage to overcome the leptin effect and keep weight off? Generally by watching their food intake very carefully and continuing to increase their physical activity. "Anybody who has lost weight and kept it off will tell you that they have to keep battling," says Dr. Rosenbaum. "They have essentially reinvented themselves, and they are worthy of the utmost admiration and respect."

I think I am in love with Dr. Rosenbaum! He gets it!

Sadie

What great information! Thank you for posting that. I am going straight to costco and getting me a big tub of leptin:drool:. Does any one know what isle it is in:lol:. Once again thanks.

cc

I just figure that much as self control and strength come into it, so much of the world's population cant be absolutely hopeless and completely self indulgent. There HAS to be biological reasons for it.

At the info evenign I went to the surgeon said that the band stays forever because although they dont know why, someone who has been previously obese just simply cannot handle the same calories as someone who hasnt. Its kind of along the same lines.

I know that I've just been away for the weekend with my sister and her pal to do a run on the Goldcoast and Lesley is 65kg compared to my 69, a few inches shorter than me and I was gobsmacked at how much that woman eats! Yes, she runs lots, but I do too and I maintain on about 1500 calories a day whilst she was putting away at least twice that. She never freaking stopped. And even my teeny 59kg sister eats more than me (she's never been fat).

Now DH is banded and is proving to be one that simply is not going to lose until he gets perfect restriction, I didnt think he overate BEFORE banding, and now he eats probably half what most men his size do and is not really losing yet.

There's definitely more to it than the conscious decisions we make. But it still up to us to take charge of it and deciding to get banded is a great first step in that battle.