Sugar: how much is too much?

This is general information, not medical advice. Always discuss your blood values with your doctor.

1. 1

   Weight: sugar works mainly through calories

   A meta-analysis of 30 trials and 38 cohort studies (Te Morenga et al., BMJ 2013) found that adults who ate less sugar lost 0.8 kg on average, and those who ate more gained 0.75 kg, in trials where they could eat freely. When sugar was swapped for other carbohydrates with the same calories, weight did not change (0.04 kg). So the effect comes from energy intake, not from a special property of sugar. In trials in children, adherence to the advice was low and no change was seen.

2. 2

   Health: mainly sweet drinks, and mostly weak evidence

   An umbrella review of 73 meta-analyses covering 83 health outcomes (Huang et al., BMJ 2023) found harmful associations between sugar intake and 18 endocrine or metabolic outcomes, 10 cardiovascular and 7 cancer outcomes, plus 10 others. Most of the evidence was observational and of low quality. Moderate quality existed only for sugar-sweetened drinks and weight, and for added sugar and fat accumulation in liver and muscle. The authors recommend keeping free or added sugar under 25 g a day and limiting sugar-sweetened drinks to less than one serving a week. That matches the stricter, conditional WHO limit of 5% of your energy.

3. 3

   The WHO limit: under 10% of your energy

   The WHO (2015) recommends keeping free sugars under 10% of total energy (strong recommendation) and, if possible, under 5%, about 25 g a day (conditional recommendation, mainly based on tooth decay). Free sugars are sugars added to food or drinks, plus those in honey, syrups and fruit juice, not those in whole vegetables and fruit or in milk. At 2,700 kcal, 10% is about 68 g. A can of sugar-sweetened soda contains up to 40 g. In Europe, adult intake ranges from about 7 to 8% of energy to 16 to 17% in countries like Spain and the United Kingdom.

4. 4

   What this does and does not say

   These limits concern the sugars in your everyday diet, not carbohydrates as fuel during long or hard exercise. That is a separate topic. The reviews mostly show associations, and for weight the effect comes from the extra energy. Drinks stand out: the strongest evidence on weight concerns sugar-sweetened drinks.

Updated in October 2026