Food and drink provide our bodies with energy in the form of calories. If we consistently consume more ‘energy’ or calories than our body uses, then this can lead to an accumulation of excess body fat. This can result in weight gain.

Worldwide, obesity has nearly tripled since 1975: 39% of adults aged 18 years and over were overweight in 2016 and 13% were obese, with over 340 million children and adolescents aged 5-19 were overweight or obese within this period. In 2018, 40 million children under the age of 5 were overweight or obese. Most of the world’s population live in countries where overweight and obesity kills more people than underweight (10).

Obesity is a complex issue, but the fundamental cause of weight gain is an energy imbalance between calories consumed and calories expended according to the World Health Organization. The increase of availability and consumption of energy-dense foods that are high in fat is a contributing factor as well as the decrease in physical activity due to more sedentary ways of life; forms of work, changes in modes of transport and increase of urbanisation (10).

Just like protein, starch and fat, sugar and sugars are a source of calories in the diet and excess calories from any ingredient or product can lead to being overweight.

Recommended calorie intake

The amount of energy we require (the average dietary energy requirement) can vary depending on gender, age and different levels of physical activity, among other things. The World Health Organization guidance sets out the percentage of your total energy intake which should come from different nutrients, including sugars and fats (11). Their recommendation is that adults and children reduce their daily intake of free sugars* to less than 10% of their total energy intake. It also advises that a further reduction to below 5% or roughly 25 grams (6 teaspoons) per day would provide additional health benefits (12).

*Free sugars are all sugars added to foods or drinks by the manufacturer, cook or consumer, as well as sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.

The best way to avoid obesity is to follow a balanced diet and keep physically active. Your doctor can advise you on the best diet for your individual needs.