The conventional wisdom is that people are eating too much and exercising too little. However, groundbreaking research suggests obesity is primarily related to a high-sugar diet.
In order for you to significantly gain weight, you must first become leptin resistant. Leptin resistance blocks the sensation of being full, making you eat more than you need.
Energy metabolism also falls, due to a reduction inimpairs your body’s ability to oxidize fat, causing a low-energy state
Sugar, and fructose in particular, is exceptionally effective at causing leptin resistance in animals, and it’s very effective at blocking the burning of fat.
Fructose stimulates weight gain through its effects on your appetite and by blocking the burning of fat. It also changes your body composition to increase body fat even when you are on a caloric restriction.
If you are insulin or leptin resistant, it would be prudent for you to restrict your fructose consumption to about 15 to 25 grams of fructose per day from all sources.