By Mark Levy, MD
The development of new neuro-imaging techniques helps physicians look into functions of the brain that was not possible a decade ago. Using these techniques, researches are trying to understand the secrets of the obesity, that great paradox of our time: half of the world is starving and another half is getting fat!
Starvation results from absence of food, but should obesity be blamed solely on excess of food? Is the answer to the obesity problem as simple as: close your mouth and exercise?
The answer from the latest scientific studies is “NO”. Okay, you may say but what is the answer? The same scientists would say: ”We do not know yet, but we will soon”.
Then the question becomes, what should we DO now?
To start with, we know that the problem of overweight cannot be completely explained by overeating. The issue is more global. According to the data released by the World Health Organization, 4.1 percent of Canada’s teenagers are morbidly obese (19.3% were found to be overweight). This means the Canadians have the fourth most obese teens in the world, behind Malta, the United States and Britain. The WHO directly and correctly characterizes obesity as a global epidemic.
In North America 23,000 weight loss or diet books were published in the past three decades. Doctors, psychologists, nutritionists, legislators and school administrators, even airline managers tried to influence people to get thin by following “the healthy diet”.
As Canadian magazine MACLEANS recently concluded: “…the traditional approach to weight loss-hoping individuals can master enough willpower to stick to a low –calorie diet and get a little exercise-clearly hasn’t worked”.
By scanning of the brains of the obese and the lean, scientists can now learn how the brain, body and food interact. What we learn is shocking: our brains are hard wired to prefer, even crave, the very foods that causes us so many problems: sweets, salt, fats and high calories. Early research has mapped the vital basic physiological structure of food metabolism. As technology improves, we will learn more details. Positron emission tomography uses increases in blood flow associated with increased activity to give a sense of which brain cells are at work. An MRI detects minute-by-minute changes in blood flow in the active areas of the brain. Those spots appear as bright colors. The brain chemistry is strongly affected by body weight. One of the neurotransmitters (messengers) is called dopamine; it is a key to the rewarding system. Dopamine gives us a sense of pleasure, but also an addiction to cocaine, nicotine and food. It makes basic functions –eating, drinking, reproducing more attractive.
The conclusion is quite simple: food may be addictive. One theory suggests that if dopamine is low, addiction to food is to augment pleasure. Dopamine is involved in memory and learning, including eating behavior.
Another theory blames genes. There are about 430 genes involved into production of obesity. New PET studies demonstrated that the center for hunger (in hypothalamus) and the center for satiety (“enough is enough”), located in prefrontal zones are less sensitive in obese compared to thin individuals. The ‘chicken or the egg” question is right here: is it that increased hunger causes obesity or does a brain abnormality with obesity causes increased hunger?
The good news is that we could learn to like or dislike certain foods. I remember that the day when I first tried pizza it was repulsive to see pieces of cheese hanging off the bread. Foreign children often strongly dislike McDonalds on their first try. They learn to like it and some of the adults eventually come to dislike it.
The real problem is that food is not the answer, at least not the whole answer. If you are around really fat people, you would feel sorry for them because they eat so little that they are literally starving themselves. When we talk about weight, many of us think about “body shape”. Many hormones are responsible for our body shape are produced in sleep. If sleep is disturbed then metabolism is disturbed. Studies from the University of Chicago confirmed that sleep deprivation destroys the hormonal profile and makes you look older.
The first lesson: if you want to be in shape – sleep well. The second lesson from sleep medicine is a confirmation of the very old saying: “Breakfast – eat yourself, lunch – share with your friend, dinner – give to your enemy”. The third lesson is: do not get extreme with any methods, even with exercise. The most important way to stay in shape is to know why and for what you want to be in shape. The last, but not the least, lesson from the history of humankind is as follows:
It is healthier to be slightly “puffier” than very skinny, regardless of whatever is fashionable. A “skinny” person will get attention, but the “puffier” one will win the race.