Understanding the problem of gaining weight
You might wonder why a psychiatrist is writing about obesity but in my practice, weight gain is a common problem among my patients. There are several reasons. Often mental illnesses such as depression make people lethargic and inactive. They eat inappropriate food and stop exercising. The medicines we use in the treatment of psychiatric problems such as depression and psychosis as a side-effect cause weight gain due to an increased appetite and derangement of metabolism. So, weight gain is often a problem patients ask my advice on.
Why We Get Fat: And What to Do About It – a best-selling book by science journalist Gary Taubes was an eye-opener for me. For years I have been telling my patients that they become fat because they eat too much – too many calories in and too little calories out and the balance calories get stored as fat. It was simple and logical. “But doctor,” they would protest, “that can’t be true. I eat so little and I work hard at my household work and hardly have time to sit down but yet I keep putting on weight.”“Aha,” I would reply with a knowing smile, “you think you are eating little but you must be eating more than you claim. Human beings, unlike plants, cannot produce food from air and sunlight. All foods must be eaten.” Watertight logic? This is the accepted teaching, but is it correct? Gary Taubes says “No. The calories in calories out model is the most misguided and damaging of the nutritional models of the last century.”
The first hint that this model might be wrong comes from the study of specific tribes where in spite of poverty and lack of food there is widespread obesity. For example, a Native American tribe in Arizona USA known as the Pima have one of the highest incidences of obesity and diabetes in the United States. It was thought that they became fat because they abandoned their traditional hunter-gathering lifestyle, became sedentary and started eating the typical American diet. But looking more closely anthropologists observed that the Pima became obese well before the Second World War at a time when the tribe had gone from affluence to poverty. So why were they fat? The answer lies in the type of food and not the quantity.
To understand this, we need to know a little about how our bodies handle food. The hormone insulin controls fat accumulation in the body. When we secrete insulin, calories are stored as fat and when insulin levels are low, the fat is released and burned for energy. Insulin is secreted in response to eating carbohydrates or starch and sugars. The more refined the carbohydrates the more the amount of insulin released into the blood.
If insulin makes us fat why does it make only some people fat? This is due to our genetic predisposition. The effect of a hormone depends on a number of factors, and depending on the particular combination of factors including our genes, insulin will partition the calories you consume into energy or storage as fat. In those with a tendency to fatten, insulin partitions a disproportionate number of calories into storage as fat rather than energy for muscles. Such persons will also have less energy available for physical activity and will tend to be sedentary.
As we grow older our cells become more resistant to the effects of insulin. Our muscle cells become resistant before our fat tissue. So, even if you were active and lean when young you will tend to put on weight as you age. Hence the reason for the ‘middle-age spread’. With less energy available for muscle older persons become more sedentary. As commonly believed, we do not become fatter with age because of inactivity but rather we become inactive because we have become fatter.
What can we do about it? Can we beat our genes even if we are predisposed to become fat? It is the carbohydrates in our food that determine insulin secretion and insulin causes fat accumulation. Not all get fat when they consume carbohydrates but for those who do carbohydrates are to blame.
All foods containing carbohydrates are not equally fattening. Concentrated carbohydrates are the biggest culprits. Concentrated sources of carbohydrates include refined flour derived bread, cereals and pasta, liquid carbohydrates like beer, fruit juices and sodas, and starches like potatoes, rice and corn. These foods are cheap calories and explain why obesity is common among poorer communities. People in low-income countries get fat not because they eat too much or are sedentary but because the foods they eat – starch, refined grain and sugar – are fattening.
In contrast, the carbohydrates in leafy green vegetables such as spinach, cabbage and lettuce are bound with indigestible fibre and enter the bloodstream more slowly and are less likely to trigger a burst of insulin. They are therefore less fattening. As these foods contain more water and less digestible carbohydrates for their weight than starches, blood sugar levels rise only slowly after eating them. As a result, the insulin response is slower, and therefore, less fattening. Fruits too have a lesser concentration of carbohydrates but contain a type of sugar called fructose. If you eat copious amounts of fruit, they too can induce the insulin response and increase the deposition of fat.
If you want to lose weight and cut back on the total amount of food you will end up by eating less fat and protein, which are not fattening and more of carbohydrates that are. The resulting weight loss will, therefore, be minimal. The resulting state of constant hunger will probably make you give up the effort quite soon. So, to have effective weight loss while cutting back on carbohydrates you should increase your consumption of fat and protein. Hang on you might say, “Is not increasing fat bad for your health? Won’t it lead to heart disease?”There is increasing evidence that this too is a myth. Eating fat per se does not lead to heart disease but rather the carbohydrates and resulting obesity is the cause.
So, if you are going on a diet reduce the fattening carbohydrates but eat all you want of protein and fat. There is another challenge however, even if we avoid hunger by eating more of proteins and fat, it will not stop the craving for some carbohydrates like sugar which is an addiction. Studies show that it may take up to one year for the craving for sweets to be lost. If you allow yourself even small amounts, the craving will continue.
Those of you who want to lose weight, keep trying, do not give up. If you stick with it you will succeed.