When someone is more than 20% heavier than the average for their height, they are classified as obese. Obesity is linked to a range of health conditions, including type 2 diabetes, high blood pressure, strokes, heart disease, cancer (breast, colon and prostate) and gallbladder disease. Every year, some 300,000 people in this country die as a direct result of them being obese. As such, obesity is more than a health hazard – it is a life threatening disease. This is also why it is so important that you understand what actually causes obesity.

It is likely that you believe that there are just two causes of obesity, which work in combination with each other. Those are overeating and lack of exercise. This is absolutely true, and inescapable. We are forced to live sedentary lifestyles due to our busy work schedules, and almost all of our food is actually processed. However, there are some other causes of obesity and if those apply to you and you also eat poorly and exercise insufficiently, you are on a slippery slope towards various diseases. Let’s take a look.

Lack of Sleep
Not getting enough sleep is a big cause of obesity, as surprising as that may sound. One prominent study, the US Health & Nutrition Examination Survey, concluded that those who sleep 7 hours or less each night are more likely to have a high BMI. Another study, the US Nurses’ Health study, concluded the same after studying 68,000 women over a period of 16 years. They found that women who sleep just 5 hours on average are heavier than those who sleep 6 hours, who are also heavier than those who sleep 7 hours. The more you sleep, therefore, the less you weigh.

It is believed that the reason behind sleep deprivation and weight gain is due to the fact that hormones become unbalanced in people who lack sleep. Particularly, leptin (which tells your body when it’s full) decreases and ghrelin (which tells your body it’s hungry) increases.

It is also a known fact that we are not getting enough sleep. We simply have too much to do every day to also spend at least 8 hours (or even 7) asleep. In the 1960s, the average American would sleep for 8.5 hours. A poll was conducted by the National Sleep Foundation in 2002, which showed that this had dropped to just 7 hours. There is a clear correlation between this and the rise of obesity.

Prenatal Effects
There is also some suggestion that you being bigger or not will, at least in part, be determined before your birth. Women who are obese are much more likely to birth babies who grow up to be obese themselves. This isn’t due solely to genetics either. Scientific evidence suggests that there is some degree of intra-uterine programming. Mice were used in a scientific study, and the babies of mice that ate food high in fat content were more likely to grow up into fat adult mice than those who were fed normal food.