There is mounting evidence that a high fructose diet is causing our metabolic systems to be out of whack. A high consumption of soft drinks doesn't seem to raise leptin and insulin levels signaling to the brain that it is time to stop eating.
To understand some of this you need to understand the role of leptin in the body. The effects of leptin were observed by studying mutant obese mice that ate voraciously. These laboratory mice either had a mutation in the gene that encodes the receptor for leptin or a mutation in the gene for creating the protein hormone leptin. When obese mice were treated with injections of leptin they lose their excess fat and return to normal weight.
Leptin is produced primarily in white adipose tissue and the level of circulating leptin is directly proportional to the total amount of fat in the body. Leptin acts on receptors in the hypothalmus of the brain where it inhibits appetite. The system is more sensitive to starvation than overfeeding. Leptin levels do not rise extensively after overfeeding.
In March 2010 researchers reported that mice with type 1 diabetes treated with leptin alone or with leptin and insulin did better (blood sugar didn't fluctuate as much, cholesterol levels went down and they didn't form as much body fat) than mice with type 1 diabetes treated with insulin alone, raising the prospect of new treatment for diabetes.
To date, only leptin and insulin are known to act as an adiposity signal. Although leptin is a circulating signal that reduces appetite, in general, obese people have an unusually high circulating concentration of leptin. These people are said to be resistant to the effects of leptin in much the same way that people with type 2 diabetes are resistant to the effects of insulin. The high sustained concentration of leptin from the enlarged adipse tissue stores result in leptin desensitation. The pathway of leptin control in obese people might be flawed at some point so the body doesn't adequately receive a satiety feeling subsequent to eating.
A study published recently suggests consuming high amounts of high fructose corn syrup causes leptin resistance and elevated triglycerides in rats. When fed a high fructose corn syrup diet rats subsequently ate more and gained more weight than controls fed a high fat, high calorie diet, www.en.wikipedia.org/wiki/leptin.
Dr. Robert Lustig, Professor of Pediatrics in the Division of Endocrinology at UCSF, did a presentation recently talking about how the biochemical negative feedback system in human beings is out of whack ( after eating the system that tells the brain I am done eating and and now is the time to burn more calories for energy). His discussion called, "Sugar the Bitter Truth", was posted on YouTube last July and nearly 500,000 people viewed the 90 minute presentation.
This is an excerpt of his presentation. In the early 1900s the average amount of fructose that people got was from eating fruit and vegetables and averaged 15 g/day. Prior to WW2 it was 20 g/day, now adolescents eat 75 g/day, 12% of their daily calories come from fructose.
In 1973, Nixon found that food was becoming a political issue because Americans were not getting enough food. In conjunction with the USDA they worked to make food cheaper. High fructose corn syrup (HFC) was created in 1966 in Japan. In 1975 it was introduced into the American diet. Corn syrup is half the price of sugar. Is is so cheap that it had found its way in everything even foods that you think won't contain it like pretzels, BBQ sauce, hamburger buns. It is added to a great many processed foods. High fructose corn syrup is more effective than glucose as a browning agent. It increases the palatability of so called "healthy foods" that have had the fat removed such as alot of the low fat snack foods on the market like Snackwells, etc...
Eating HFC doesn't supress gruelin- the hunger hormone signal. There are no receptors for fructose. Insulin and leptin don't increase with increased consumption of soft drinks (doesn't tell the brain that it is time to stop eating).
Sports drinks have alot of HFC. These drinks replete glycogen faster in athletes than water. Who are drinking the sports drinks ? Kids are because it is the "cool" thing to do and it tastes good. In 1967 Gatorade was created for athletes and it tasted bad. In 1992 Pepsi bought it and added alot of HFC. Overweight kids drink it.
When we consume glucose 80% of it is used by all the organs. Every cell uses the glucose. It is the energy of life. The rest hits the liver and is stored in the liver as glycogen. This is the nontoxic form of glucose and any amount can be stored in the liver. There is negative feedback system between glucose, the liver, the pancreas and the brain (this helps to prevent overeating). If you compare the metabolism of a can of Coke and a can of beer a large % of the calories hit the liver. Both are metabolized like fat. Fructose is ethanol without the buzz. Fructose has no brain metabolism only by the liver.
Rats that are glycogen depleted, when they are refed with sucrose more of the calories are metabolized as VLDL and then turned into triglyceride. Basically hepatic fructose is metabolized into triglyceride. Medical students given glucose had none of it ending up being converted to fat. On a high fructose diet 30% of the calories ended up as fat. It is just like consuming fat. A high fructose diet is a high fat diet.
How does this translate in preventing obesity in children ?
* Get rid of every sugared drink in the house like Gatorade, juice and soda. Have a big pitcher of water flavored with orange slices and mint in the refrigerator. Water down the juice. Mix juice with club soda.
* When carbohydrates are eaten make sure it is high in fiber. When adding high fiber foods such as whole wheat bread, whole wheat rice, whole wheat crackers, whole wheat pasta, whole wheat cereal, raw fruits and vegetables, etc... satiety is signaled sooner.
* Look at the Paleolithic diet, it talks about eating a diet similiar to Cave men where they ate everything that came out of the ground raw, 100-300g. of fiber. This has great promise in helping with blood sugar control.
* Look at the ingredient list on products for high fructose corn syrup, fructose or sucrose. It is better to have glucose in the ingredient list or of course things like splenda or equal. (It is everywhere, HFC is in chocolate milk and baby formula is 40 % corn syrup solids and 10.3% sugar. The earlier a child is exposed to the sweet flavor, the more they crave it later in life).
* Be creative with snacks. If your child is tired of raw fruit and veggies, microwave sliced apples and then flavor them with cinnamon and Splenda. Bake big chunks of carrots in the oven with some butter and flavor them with Splenda and cinnamon.
* For a different taste try whole wheat crackers or bread and spread with pecan butter or another nut butter like almond instead of peanut butter.
** Snack ideas are my own. Some of this information applies to type 1 diabetes, some of it applies to type 2 diabetes and some of it applies more so to obesity and children.
* Eat and wait 20 minutes for the satiety signal.
* Match screen time (computer, video games, tv) to playtime outside. Exercise increase insulin sensitivity and helps reduce insulin levels. The more insulin sensitive you are, as in type 2 diabetes, the better glucose is metabolized.
* Reduce stress this will decrease eating due to stress.
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