Obesity means having too much body fat. It happens when you eat more calories than you use. The balance of calories in and calories out is different for each person. Factors that can affect this balance include diet, physical activity and genetics.

Obesity is a large and growing problem — pun intended. Worldwide in 2014, more than 1.9 billion adults aged 18 years or older were overweight. Of these, over 600 million were obese. The number of obese people in the world has more than doubled between 1980 and 2014. Most of the world’s population lives in countries where obesity kills more people than being underweight.

Increasing age is a risk factor for obesity, in part due to hormonal changes and a less active lifestyle. Also, the amount of muscle in the body tends to decrease with age, leading to lower metabolism. These changes also reduce calorie needs, which can make it harder to keep off excess weight. If you don’t control what you eat and become more physically active as you age, you’ll likely gain weight.

Certain medical conditions can increase the risk of obesity. Some medications can also contribute to weight gain. Yet, healthy people can gain excess weight as well. In particular, increased intake of energy-dense foods that are high in fat has become a major cause of obesity.

Loss of opportunity for physical activity has also worsened the obesity epidemic. In recent decades, an ever-growing number of “desk jobs” made our lifestyles more sedentary. We walk much less than in the past, preferring instead to drive or take public transportation. More people live in large cities now than ever before. This lowers travel distances and otherwise relieves dwellers of any lengthy physical effort.

You may be saying to yourself: “This does not apply to me. I am not obese!” Try the following experiment: Take your height in metres and square it. For example, if you are 5ft 9in tall, that equals 1.75 metres. If you square this number, or multiply it once by itself, you will get 3.06. Now divide your weight in kilograms by the square of your height. For example, if you weigh 176 pounds, that equals about 80Kg, so you divide 80 by 3.06 and you get about 26. This final number is the Body-Mass Index, or BMI. The World Health Organisation states that:

Persons with BMI that is equal to or more than 25 are overweight.

Persons with BMI that is equal to or more than 30 are obese.

Being obese increases the risk of diabetes, heart disease, high blood pressure, stroke and some cancers. Excess weight can also diminish your quality of life. You may not be able to do things you used to do, such as participating in enjoyable activities. You may avoid public places. Obese people may even encounter discrimination. There are many other weight-related issues that may affect your quality of life. Some of them include depression, disability, sexual problems, shame and guilt, social isolation and lower work achievement.

The good news is that even modest weight loss can improve or prevent the health problems associated with obesity. Here is what you can do to achieve and maintain healthy weight:

• Limit the intake of simple carbohydrates. Sugar, fruit juices, sodas, sweets, rice and potatoes are among the most serious offenders in this category;

• Limit the fat intake and avoid saturated fats and trans-fats. For example, baking shortening, frying oil used in restaurants, red meat, margarine and dairy milk contain trans fats. Fatty beef, pork, lamb, chicken skin, butter and cream contain saturated fats;

• Increase consumption of fruits and vegetables, legumes, whole grains and nuts;

• Increase physical activity. Work with your doctor to develop a safe and effective exercise programme, and follow it;

• Prescription medications and weight-loss surgery are other options for treating obesity.

Losing excess weight and keeping it off requires a long-term, sustainable change in lifestyle. The necessary adjustments may not be easy to make, but are definitely worth the effort. Healthy weight will likely reward you in the form of better health, more fulfilling life and longer lifespan.

•Mike Serebrennik is a physician by training and now a full-time entrepreneur, investor and writer. He is also a director of product development and sourcing at Lighthouse Medical Supplies, Ltd — a local company dedicated to helping patients and healthcare providers lower the cost and increase the quality of care.