What’s Really Behind The Childhood Obesity Epidemic
Robert Lustig, M.D.
Dr. Lustig is currently Professor of Clinical Pediatrics in the Division of Endocrinology at University of California, San Francisco and Director of the Weight Assessment for Teen and Child Health (WATCH) Program at UCSF.
The Skinny on Obesity by Dr. Lustig
Update: See Dr Lustig’s YouTube talk, Sugar: The Bitter Truth given at UCSF Mini Medical School for the Public 2009-07
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Summary And Implications for Daily Life
by Dave Yost, edited by Robert Lustig, M.D.
This was a long, detailed, fascinating, convincing, wide-ranging talk. The implications are massive. I believe that the excellent work Dr Lustig presented here is the beginning of the end for the big business of sugar addiction. It couldn’t come a moment too soon because we are bankrupting ourselves and our descendents with the health problems we are buying in the form of sugared products and then paying for again in medical care.
Preventing and reversing obesity and overweight is pretty simple, once you see the science behind it, presented to us by Dr. Lustig. It goes like this:
Eating sugar spikes insulin, which after a while makes you insulin resistant. By now, most of us have heard this. But this is only the half of it.
Becoming insulin resistant also makes you leptin-resistent
Leptin? It’s a crucial hormone that has only become understood in the last few years. Leptin tells your brain whether you’re starving or not; not enough leptin and the starvation alarm bells go off until your brain gets enough leptin again. If either your body doesn’t make enough leptin or your brain is resistant to leptin, the effect is the same: your brain gets the signal that you’re starving.
When your brain is in starvation mode, it makes you feel like you are in an emergency requiring food; the body slows down your metabolism and your desire to expend energy; you become constitutionally sedentary; and your body works even harder to store sugar as fat. If you now try to eat less, these impulses just get stronger. In this mode, you can still put on weight even if you’re eating a lot less!
So: if you’re overweight, you’re insulin resistant. If you’re insulin-resistant, you’re leptin resistant, and you’re in a vicious cycle.
The solution
First, reverse the insulin resistance, and in doing so, you reverse the leptin resistance. This takes some weeks of cutting out all sugared food and drinks. Evenpure fruit juice is bad because the fiber has been eliminated. Eat the whole fruits. Look carefully to be sure neither sugar nor corn syrup are added to what you eat. (For example, V8 has sugar added.) Don’t eat refined starches or starchy foods without fiber (refined wheat, pasta, potatoes, white bread, white rice). A simple rule of thumb: eat your carbohydrate containing their own fiber: legumes, nuts, vegetables, and some fruits. Give your body a chance to reverse the insulin resistance without trying to cut down on how much you eat. Just cut off the bad stuff. For liquid intake, drink only plain water, never even 100% fruit juices.
Your leptin and insulin systems will move toward working properly again. Your body will relax its panic-mode cravings. You will feel less urge to eat. What you eat will be less urgently pushed into making more fat. You will feel like moving around more and using more energy. You will feel better!
The other big villain is, believe it or not, fructose. Sugar (sucrose) is 50% fructose and 50% glucose. High-fructose corn syrup, which has come into our food supply only in the last 20 years, is 42 or 55% fructose (and the rest, glucose), so HFCS is just as bad as regular sugar. Why? Because fructose is utilized by only one kind of cell in the body, the cells in the liver. It is basically toxic to these liver cells and causes insidious trouble with your insulin system, leading to the leptin problems. In moderation, the amount of fructose you get from whole fruit (not juice) is OK because it comes with enough fiber to keep it from hitting your liver too hard too fast. The juice is there in fruit to get you to eat the fiber in the whole fruit.
The above comes from a massive amount of first-rate molecular and biochemical science and a lot of clinical trials. It is not just yet another bunch of stuff dreamed up by someone who wanted to write a diet book and get rich. You may have heard all of the above before, but now there is a mountain of good science to prove it. And of course, it’s not just about weight. It’s about your energy level, your brain power, diabetes, heart disease, stroke, and on and on.
For more details, see The Skinny on Obesity – an additional article submitted by Dr Lustig
Thank you, Dr Lustig, and good luck when you give this talk at NIH this weekend.
- Dave Yost
- SLF board member
The great Linus Pauling warned that research pointed to fructose being a big problem. You can find his discussion of this in chapter 6 of his excellent 1986 book (reissued in 2006), How to Live Longer And Feel Better.
