Major Breakthrough in Obesity Research
There has been a giant breakthrough in the understanding of obesity since 2006! There is much more chemistry involved than we originally thought. We have discovered that fructose, in the form of high fructose corn syrup, table sugar, and fruit juice, has been been poisoning our bodies by interfering with leptin, insulin and other hormones. These food hormones control the amount of food that is stored as fat, so when they are poisoned, the body stores energy in fat cells, and very little is left over to use for activity. The brain is deprived of energy too, so it produces other hormones that make you hungry and you want to eat more high-energy foods.
Thus, your fat cells are stuffed, but your brain is starving, so it can't function as well, plus it wants you to eat more!
In the past we already suspected that eating too much sugar was bad, but we thought it was just the extra calories. Now it is known that the fructose in sugar is poisoning our hormones. This effect results in increased insulin, which makes the energy from the food you eat go straight into fat cells, and even if you try to exercise to lose weight, you don't have the energy available to do the exercise.
Fructose is processed by your liver, converting it to free fatty acids and triglycerides (the "bad cholesterol"), putting you at risk for heart disease, stroke, cancer, liver disease, diabetes and other health risks, even if you eat a low fat diet.
Fructose Poisons the Fat and Energy Control Mechanisms
Fructose is quickly absorbed by the intestines and enters the liver where it is converted to triglycerides and free fatty acids and other fats. These are then released into the bloodstream. Free fatty acids are known to make muscle cells insulin-resistant. Insulin resistance means the cells do not respond to insulin, so the body keeps trying to make more insulin to overcome the resistance. Excess insulin then builds up throughout the body. (Sorry this is so complicated!)
Excess insulin blocks the effect of the hormone leptin on the hypothalamus (an important part of your brain that controls energy and basic body functions). Leptin is normally produced by your fat cells and tells your brain when you have enough or too much fat. On top of that, the triglycerides block the leptin from entering your brain.
Leptin normally stimulates your hypothalamus to go into "energy burning mode":
1. reduced appetite
2. increased thyroid hormone, with increased energy expenditure
3. increased stimulus to muscles, releasing heat
4. increased fat breakdown, to supply more energy
5. feeling of well-being, desire for activity
When leptin is blocked by too much insulin and triglycerides, the hypothalamus goes into "energy saving mode":
1. slowing the heart rate, and decreasing energy use in your muscles
2. increasing the motion of your intestines (hungry growling stomach) and increased food absorption
3. increased insulin production, which causes your body to store energy in your fat cells
4. desire to be sedentary
When kids (or adults) get to this point, they start seeking more high energy foods, like fats and sugars. They eat more fructose, and the whole vicious cycle gets worse! This leads to a hyper-insulin state, where too much insulin is produced, more energy goes into the fat cells, and the brain is further starved. Excess insulin can also result from eating too much fat or too little fiber, or from having a sedentary lifestyle.
Why is there so much fructose in our diets?
Over the last few decades, high fructose corn syrup was discovered to be a cheap source of food energy, which also had the marketing advantage of being "addictive" because it makes you want more and more. Today almost all sweet processed foods contain this, since it very cheap to add, and increases sales since it starves our brains and makes us want to eat more.
What is High Fructose Corn Syrup?
Natural corn syrup contains glucose, which is the simple sugar used by our bodies. It does not taste very sweet, so food manufacturers add enzymes to corn syrup to convert the glucose to fructose which tastes very sweet. High fructose corn syrup is 55% fructose! Unfortunately, fructose is toxic to our bodies.
Reading labels to look for fructose or high fructose corn syrup can help us spot the foods that should be avoided. Also realize that all table sugar (sucrose) is half fructose, so cut back on regular sugar as much as possible. Most of the food we recognize as "junk food" probably is high in fructose or sucrose.
Another source of fructose is fruit juice. Many schools have made the misguided choice to remove soft drinks from their vending machines and replace them with fruit juice. The soft drinks have too much fructose in the form of high fructose corn syrup, but even 100% natural fruit juice has more fructose than full-sugar soft drinks! The American Academy of Pediatrics has been advising children to strictly limit juice intake for several years now.
What is safe for kids to drink?
Water is always the best fluid to drink, so doctors encourage everyone to drink plenty of water. There are many sweet drinks that are made with artificial sweeteners, such as aspartame, saccharin, and sucralose. These do not have fructose, are very low in calories, and have no known harmful effects on humans. There have been some concerns raised about sweet drinks, that they may increase the desire to eat or drink other sweet foods or drinks which may contain fructose. There is also a concern that certain sweeteners may have some of the insulin-increasing effects that fructose has, but this has not yet been studied in humans. (There was a study in rats which showed increased insulin from aspartame.)
There are some concerns that the long-term effects of sweeteners have not been studied. We may be well to think of these as a "nicotine patch" to wean us off our high sugar diet, but not to use them heavily.
Bottom line: right now most doctors are recommending that diet drinks are OK, since these are far less harmful than sugar drinks. The best fluids to drink are water, and 2 or 3 cups a day of low fat milk.
[Source: "How Our Western Environment Starves Kids' Brains" by Dr Robert Lustig, Pediatric Annals 35:12, December 2006]
Learn a whole lot more at www.healthyweightkids.org