It’s not that you get fat by eating too much or exercising too little, says Dr Richard Johnson, a leading kidney specialist at the University of Colorado. “You are gaining weight because you have changed your ability to regulate your diet.” And suffering metabolic syndrome means a raised risk of kidney, liver and heart disease as well as cancer.
Fructose causes obesity and metabolic syndrome by encouraging you to eat more and by clogging your cells’ energy generators, Johnson explains. “Our work also shows that sugar or fructose induces resistance to leptin,” which is the hormone the body uses to signal fullness to the brain. It also regulates how energetic we feel. Eating too much sugar, especially too quickly, eventually leads the brain to miss the “I’m full now” message.
Even when Johnson put lab animals, fed plenty of fructose, on a calorie-restricted diet, they still developed metabolic syndrome. Fructose primes the body: “When you eat fructose it makes [weight gain] real easy. The firewood is fat, but fructose is the fire,” is how Johnson explains this unhealthy fat-sugar duet.