Obesity: "We're not going to put that genie back in the bottle". This is the firm belief of Professor Barbara Hansen, a leading US scientist in the field of obesity.

Professor Hansen, who works at the University of South Florida based in Tampa, became famous as a result of her long-running experiments with monkeys. By giving them a lifelong near-starvation diet she has proved that obesity can be prevented and that this has a very beneficial effect on general health.

Trying to fix the problem
Generally speaking there are four traditional ways of treating obesity or trying to make obese people lose weight. Professor Hansen ruthlessly attacks all four of them:

"The first is changing diet composition; that has nothing to do with reducing bodyweight."

What Barbara Hansen is referring to in this case are diets, which claim good results by reducing the relative amount of carbohydrates (like the famous Atkins diet) or by increasing the amount of proteins. The idea behind it is that the person following this diet can eat as much as he or she wants and still lose weight. But Dr Hansen is adamant,

"a calorie, is a calorie, is a calorie, there is no advantage or disadvantage to any of the usual diets that are out there". 

Exercise 
The second - and very popular - way of losing weight is exercise:  "The facts don't support that weight loss in an obese person can be achieved by physical activity alone."

This, according to Professor Hansen is mostly to do with the duration of the exercise: typically what physicians recommend is 30 minutes a day, five days a week of brisk walking. This is about the amount of exercise that can be expected from a middle-aged overweight or obese person.

There are two problems with this theory: firstly, it takes tremendous discipline to stick to this training schedule, too much discipline in fact, so it just won't happen. Secondly, by walking 30 minutes a day, 1000 calories can be burnt off in a week. The normal daily consumption for an adult male just to maintain his weight is 2500 calories: that adds up to 17,500 a week. A reduction of a mere 1000 calories just isn't going to have any measurable effect.

Drastic
The third method of treating obesity is the most drastic one: surgery. Professor Hansen explains:  "Essentially this means limiting the gastric capacity and forcing people by mechanical means to eat less. This is very effective, it produces massive weight loss in very overweight people who on top of that usually keep the weight off."

"However, this is an acceptable method only for the massively obese, it is not a procedure for 'normal' obesity". And then there are drugs, pharmaceuticals, the fourth and newest method of weight reduction. These days there are three prescription drugs on the market with a weight-reducing effect. Professor Hansen: "All three of those drugs produce modest weight loss. Over a period of about two months people lose something like four to eight kilogrammes, in that range. They generally level off,  and they end up losing something like four to six kilogrammes."

"A reduction of five percent max. Anyway, the effect wears off, and as soon as they stop the medication they immediately regain it." 

Prevention?
Of course, all this raises the question of whether it wouldn't be better to prevent obesity from happening in the first place. But, unfortunately, nobody knows how to do that. Barbara Hansen's research may have proved that calorie restriction works in lab monkeys, but people aren't monkeys, or as the professor puts it: "Obesity, I'm afraid, is mostly genetic in a permissive environment. Now, what about a permissive environment; well we're not going to put that genie back in the bottle."

"There is no way we're going to go back to a time of poverty, a time of calorie restraint because of inability to get adequate food."   

Be realistic 
This is why Professor Hansen urges those who are battling obesity to be realistic. It's simply not possible to make an obese person slim again, so better to treat the complications of obesity as well as possible. "That we can do. We can treat hypertension, we can treat diabetes. But the reality is, we really don't know how to prevent obesity".

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