Nowadays, more than one in two adults and nearly one in six children are overweight or obese in OECD countries and nearly 20% of the world´s population is obese or overweight. That is expected to increase during the next years. Childhood obesity is a major concern as it affects almost 31%.But perhaps, we should try first to determine what does obesity mean. What is the difference between being overweight and being obese? Are there different types of obesity? What is the best way to calculate it?Overweight and obesity are defined as an abnormal or excessive accumulation of fat that can be harmful to health. And of course, the simplest way to measure it is by comparing it to the height according to what is known as the Body Mass Index, which is calculated according to following equation:

WHO defines overweight and obesity in adults as follows:

• overweight: BMI equal to or greater than 25.

• obesity: BMI equal to or greater than 30.

Regarding obesity in children, it would be necessary to compare the result with Comparing body measurements with the appropriate age- and sex-specific growth.


However, the health risks associated with overweight depend on where it is located. Obese people may have a greater accumulation of fat in the buttocks, thighs and arms (peripheral obesity or gynoid), or accumulate mainly in the abdomen and internal organs (central obesity or android). Actually, this central obesity presents a greater risk of suffering cardiovascular diseases. The easiest way to do it is to measure your waist at the navel level, that is called the abdominal perimeter. Any waist circumference greater than 88 cm (35 in) in women or 102 cm (40 in) in men will be classified as obese.

Undoubtedly, energy intake and energy expenditure is the underlying cause for fat accumulation and the amount of energy the body gets from food depends on the type of food, cooking techniques and the time elapsed since the last meal. Simultaneously, the lower energy expenditure (physical activity), the stronger tendency to accumulate body fat. There are other several reasons to store excess fat as endocrine disorders such as hypothyroidism or taking some drugs such as antidepressants or corticosteroids (remember yo do not stop taking any pill without talking to the doctor who prescribes it for you).

But what are the risks associated with being overweight? And above all, how to avoid them?

The problem of obesity is not just a matter of aesthetics. Obesity decreases life expectancy and increases the risk of other serious health problems, especially cardiovascular diseases such as hypertension, heart disease (acute myocardial infarction) and brain (stroke). In addition, obese patients most commonly suffer from diabetes mellitus, gout, and elevated cholesterol and triglycerides.

The ideal treatment of obesity is prevention. Parents, teachers, the media and governments must promote healthy foods and healthy eating habits, as well as ecourage and facilitate the development of physical fitness from very young.

Once we have a problem with excess weight, the solution is to achieve a negative energy balance. This is not only achieved by reducing caloric intake (a 1,500-calorie diet will help you lose 1 pound per week) but also must be accompanied by changes in healthy eating habits (plan meals, frequency, eat more slowly, liquids, rest after meals, ...). Remember the importance of daily physical activity. We should also know which kind of exercises contribute to achieving greater weight reduction (aerobic exercises such as walking, running, cycling, swimming, ... are the most appropriate in this case). A nutritionist and dietician will greatly help you achieve and maintain the success of weight reduction.

When nutritional measures are not enough, we have the option of adding one of the few diet drugs available. Sibutramine, orlistat, or bupropion are some examples, although none of them are free of side effects that you should know and consult before you start taking them. In some countries the human analogues of glucagon-like peptide type 1 (GLP-1) are being used, as injectables to achieve major weight reduction (it has been reported even more than ten kg).

In those cases where obesity does not respond to dietary measures and becomes a serious health problem, weight reduction surgery (bariatric surgery) may be necessary. There are different types of surgeries such as the placement of an adjustable gastric band (restrictive technique), techniques with resection (vertical gastrectomy), malabsorptive (biliopancreatic diversion) or mixed (gastric bypass) techniques. Its potent short- to medium-term efficacy has now made it a valid therapeutic option for type 2 diabetes mellitus in obese patients. By contrast, bariatric surgery can have negative effects by altering the processes of digestion and absorption of nutrients, trace elements, vitamins, etc.

Finally, obesity is a serious public health problem that affects children and adults, in developed and developing countries, and has been allocated a large amount of economic and human resources for its management, control and prevention, but the key to success for all of us is to raise awareness and adopt healthy habits of life.

You must not forget either that these are general recommendations and that treatment must always be individualised, that is, adjusted to your particular case. Therefore, we recommend medical supervision before any change in your treatment.