If Rats Consume A Lot Of Fructose, And Have A High-calorie, High-fat Diet, They Become Overweight

How is this possible?

"The University of Florida researchers hypothesized that a high-fructose diet could lead to leptin resistance, which in turn could lead to exacerbated weight gain in the face of a high-fat, high-calorie diet, a typical diet in industrialized countries. To test their hypothesis, the research team performed a study with two groups of rats. They fed both groups the same diet, with one important exception: one group consumed a lot of fructose while the other received no fructose.

Two groups similar over six months

During these six months, there were no differences in food intake, body weight, and body fat between rats on the high-fructose and the rats on the fructose-free diets. In addition, there was no difference between the two groups in the levels of leptin, glucose, cholesterol or insulin found in their blood. There was only one difference at the end of the six months: The rats on the high-fructose diet had higher levels of triglycerides in their blood.

The researchers next tested the animals to see if they were leptin resistant. They injected all the animals with leptin, to see if they would respond by eating less. Animals whose leptin response is functioning normally will lower their food intake. The researchers discovered that the rats on the high-fructose diet were leptin resistant, that is, they did not lower their food intake when given leptin. The no-fructose animals responded normally to leptin by eating less.

This first six months of the study showed that leptin resistance can develop silently. 'Usually, leptin resistance is associated with obesity, but in this case, leptin resistance developed without obesity,' Shapiro said. 'This was very surprising.'

Role of diet

Having seen that leptin resistance could develop silently, the researchers next wanted to find out what would happen if they switched the rats to a high-fat, high-calorie diet -- the kind many Americans eat. They found that the animals exposed to the high-fructose diet, the leptin resistant rats, ate more and gained much more weight and fat than the leptin responsive animals on the fructose-free diet."
Clearly there is something odd about this research.

In order to allegedly "prove" their point, the researchers had to inject the animals with exogenous leptin, since naturally produced leptin did not get them the results they wanted, i.e., "there was no difference between the two groups in the levels of leptin, glucose, cholesterol or insulin found in their blood."

The roles leptin and other substances may play in the body remain unclear.

What is clear is that these experts found their results "very surprising," i.e., they have no idea what leptin really does and in a natural setting, i.e., without injecting leptin into the rats, their alleged high-fructose intake, had no real effect.

There remains a bottom line - no one knows what is going on, with one exception.

That exception is Calories in, Calories out.

This will never fail you or anyone or any living creature in altering its weight.

Consume more Calories than you burn to gain weight.

Consume fewer Calories than you burn to lose weight.

Consume the same number of Calories that you burn for a stable weight.

Period.

Unless you are David Katz and Jorge Cruise. Then this is not true. They are wrong.

They are endorsed by Oprah. (see here, here and here)

She is wrong.