Can sugar contribute to obesity? Yes.
Can a person eat a lot of sugar and remain thin? Also yes.
Plenty of thin people eat a diet high in refined sugar. Think of all the teens who live on soda and fast food. Therefore, logically, sugar is not the sole cause of obesity. Of my four children, my son who never has to worry about his weight eats more sugar than his siblings, yet remains thin without trying.
There is little doubt that eating more calories than the body consumes leads to obesity. But does the body care if the calories come from sugar or from a healthy balance of fruits and vegetables, meat and potatoes?
At least in many instances, it seems the answer is no. When patients enter the hospital they are commonly given IV fluids which are primarily sugar water. Many of these patients lose weight, despite taking most of their calories in the form of glucose. Cancer patients and others with serious illness survive on tube feeds alone for months or years at a time. Many of these patients lose weight, despite the high carbohydrate content of the liquid diet. The total calories taken in is simply insufficient to meet the needs of the body. The body feeds on itself to make up for inadequate diet, and weight loss results.
On the other hand, patients who are already overweight or obese often develop a craving for sugar or simple carbohydrates, and find these foods tend to maintain or worsen the overweight condition.
Just what gives here? Do doctors and scientists understand what’s going on?
A few years ago they thought they had the answer. The discovery of leptin deficiency in massively obese mice led scientists to believe they had the answer for overweight humans as well. Leptin tends to inhibit appetite. The lack of this hormone makes mice (and people) eat voraciously. However, it turns out that most overweight people have more leptin than thinner people. The biologic system that controls appetite and weight turns out to be much more complicated than previously understood.
Scientists did discover that certain humans have the mutation that leads to leptin insufficiency and obesity at a young age. Treating these children with leptin does help lower their body weight considerably.
But what about the middle-aged adult who has seen the spare tire inflate over the years? Currently we have no good answer except to eat less and exercise more. Avoiding sugar is not a bad idea – it’s so difficult to limit intake to a reasonable amount that total abstinence may be an easier answer. But other simple carbohydrates may be just as bad for the body: white bread, white rice, white potatoes, breakfast cereal, and pasta.
The healthiest diet is one that consists primarily of vegetables and fruits, yet many find this unfulfilling. No matter what the scientists discover, a pill can’t be the answer for modern man. We simply need to exercise more and eat healthier. The very thought makes me hungry for a piece of cake. What’s a person to do? I’m pretty sure if we had to grow our own food we’d all be thinner – I know I would be. Can I use my teenagers for an excuse for now?
Copyright 2010 Cynthia J. Koelker, M.D.