What Causes Obesity?

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I had a friend, Pramod. He was an early riser and used to go for morning walk religiously every morning. But while coming back, he would never forget to gobble four samosas (triangular pastries with fillings like potatoes, onions and peas) and a full plate of jalebis (sweets made by deep-frying maida flour batter in circular shapes and then soaking in sugar syrup) at one of his favourite restaurants.

Samosa and jalebis

Eating too much and moving too little or not that much led to positive energy balance and weight gain and thus he invited various risks to health. But Pramod is not alone. We may come across a number of people who may be blamed for bringing in the current epidemic of obesity. Normally a person with a body mass index (BMI) over 30 is considered obese.

The question is whether only overeating causes obesity.  Higher the calorie intake, higher the obesity? Is it such a simple mathematical equation?

I came across a study, findings of which had been published in the American Journal of Clinical Nutrition. It revealed that modern dietary patterns characterised by excessive consumption of foods with a high glycemic load was mainly responsible for causing obesity.

The study points out the flaws in the energy balance model (EBM) that asserts that all calories are alike for the body, and that body weight can’t change if intake and expenditure of energy are equal over time. When intake exceeds expenditure, it adds to body weight. It doesn’t explain the biological causes of weight gain.

The carbohydrate insulin model (CIM) claims that foods with high glycemic load carbohydrates produce hormonal changes that promote calorie deposition in adipose tissues, exacerbate hunger and lower energy expenditure.

Glycemic Index (GI) indicates how rapidly a specific carbohydrate food raises blood sugar. Most fruits, carrots, kidney beans, chickpeas, lentils etc are foods that have low GIs, while white rice, white bread, cakes, cookies, sweet treats, sweetened dairy products, chips, potatoes and fries have high GIs.

When we eat highly processed carbohydrates, the body increases insulin secretion. This in turn signals fat cells to store more calories leaving fewer calories for other muscles and tissues. The brain then perceives that the body is not getting enough energy that leads to the feelings of hunger. As a result, we eat more, as we tend to remain hungry despite gaining excess fat.

So instead of asking people to eat less, the focus should be on what they should eat. The issue is still open to further researches for coming to a conclusive evidence. But till then the old golden dictum of a good diet, exercise and a proper night’s sleep needs to be followed for a healthy life.

–Kaushal Kishore