Panasonic Youth

Kathy Sierra, the Shangri-La diet, and common sense

Kathy Sierra recently blogged about her positive experience with the Shangri-La diet (no link love from me). I love Kathy’s blog, her books are great, and she is a great presenter. But she should stick to mind hacks and learning theory instead of advocating diet books.

While, I commend her on success in losing weight, its disappointing to see her promoting a book based on “self-experiments” and bad science. From Kathy’s post:

A UC Berkeley professor named Seth Roberts claims to have found a way to trick the legacy brain into thinking it needs to weigh less. (Which means "lower your set point", for those who are familiar with that term)

She goes on to say how its not based on any drug/supplement use, and doesn’t require exercise or changing what you eat. Oh, and its based on rat studies.

Where to begin. First of all, the idea of your body having a set-point is well established in the literature. Basically, your body wants to stay at a certain body fat level, and the more you try to get below that (ie get lean), the more your body will fight you. Your set point is set pretty early, probably around puberty, based on genetics and possibly your diet in the early part of your life. All the signals that really make up your set point come from your brain, and have to do with leptin, ghrelin, and a whole bunch of other chemicals that are all interrelated and highly complex.

So your set point is a big reason why its so hard to lose weight and keep it off. The problem with Roberts’ claims are this: once you are an adult, your set point can go up, but its not going to come down. You can diet like crazy and stay lean for years on end, and your body will not reprogram itself to that lower level of leanness. They have followed post-dieted people for years after they’ve successfully less weight, and they still show evidence of being well below their set point (depressed metabolic rate, slower fat burning, etc).

Oh, and the rat studies? Studies in rats and other animals are notoriously unreliable in applying their results to humans. Researchers find it hard enough to do good studies with human subjects regarding diet, particularly where participants self-report food intake. But thats a whole ‘nother issue…

Lyle McDonald, who is insanely obsessed with this stuff and well known for his expertise, has commented often about this. For instance, from this thread: <blockquote>I have looked for years and seen exactly zero data to suggest that setpoint ever comes back down…….My hunch: if setpoint ever truly adjusts itself back down, you have to get and stay lean for years on end. [emphasis mine] Which, given most people’s tendency to regain weight, might as well be saying that it never occurs.</blockquote> If there ever is a way to really adjust set point down, its going to be via drugs that operate at the brain level. You can bet big pharma is pursuing this like crazy, but the complexity of the systems involved is daunting.

This makes sense from an evolutionary perspective, because up until very very recently obesity was not a major concern for survival. Starving to death during famine has been. Heart disease and diabetes are pretty new on the scene. It makes sense that we would be programmed to fight very hard against weight loss but not against weight gain.

So Roberts tricks with sugar water or olive oil or whatever all really come down to what every fad diet come down to: they trick you into eating less. One possibly explanation is that you follow the regimen of not eating anything for two hours in a day, and you subconsciously eat better the rest of the day to avoid messing up (despite whatever Roberts says about eating whatever you want). Besides, drinking only water or a small amount of olive oil for two hours a day is far more control then most people have over their diets, so its not surprising that people see weight loss when they actually start thinking about what they eat and feel in control of their food intake for once.

So if Shangri-La, Cabbage Soup, Beverly Hills, or the Zone works for you, great! Just realize that it comes down to eating less and moving around more, and not food combining, supplements, or trying to trick your body’s set point. Use whatever tool, diet, or book that helps you get into better eating and exercise habits you can sustain long term. But please, don’t chalk up the success to psuedo-science, voodoo, and rat studies.

(now, I really should do something with those fithackr/er domains….)