Sugars

Sugars are simple carbohydrates that taste sweet. They occur naturally in fruit, vegetables and milk, and are added to drinks and foods such as sweet beverages, desserts and sauces. The type and amount matter: added sugars are the ones to limit.

What is it?

Sugars come in two sizes. Monosaccharides are single sugar units: glucose (the body's main fuel), fructose (fruit and honey) and galactose (from milk sugar). Disaccharides are two units joined together: sucrose (table sugar: glucose plus fructose), lactose (milk sugar: glucose plus galactose) and maltose (malt sugar: two glucoses).

Natural sugars in whole fruit and milk come with fibre, water, vitamins and protein. Added or "free" sugars — table sugar, syrups, honey, fruit juice and sugar in sweetened drinks — provide energy with little else.

What it does

1. Provide quick energy, at about 4 kilocalories per gram
2. Glucose is the preferred fuel for the brain and red blood cells
3. Make food more palatable

Food sources

Naturally in fruit and milk; added to soft drinks, bubble tea, sweetened coffee and tea, juice drinks, cakes, biscuits, sweets, chocolate, ice cream, desserts, breakfast cereals, flavoured yoghurt and many sauces.

Singapore food examples

1. Sweet drinks — bubble tea, sweetened coffee and tea (kopi, teh), canned drinks, sugarcane juice and fruit juice
2. Desserts — ice kacang, chendol, bubur cha cha and kueh
3. Kaya, condensed milk and sweetened sauces
4. Order "kosong" (no sugar) or "siew dai" (less sugar) for kopi and teh
5. Look for the Nutri-Grade label on drinks, and the Healthier Choice symbol on packaged foods
6. Eat whole fruit rather than juice

How much do I need?

Singapore's dietary guidelines recommend that added sugar provide no more than 10 percent of daily energy — about 10 teaspoons (around 50 g) of sugar on a 2,000-kilocalorie diet — and that cutting to about 5 teaspoons (25 g) is even better. See Singapore's dietary guidelines for adults (HealthHub). There is no minimum requirement for added sugar.

Low intake and deficiency

There is no deficiency from avoiding added sugar. The body makes the glucose it needs from other carbohydrates, and from protein and fat when necessary.

Too much and safety

A high intake of added sugar, especially in drinks, adds energy without making you feel full, and is linked to weight gain, tooth decay, type 2 diabetes, fatty liver disease and heart disease. Liquid sugars are the biggest concern.

Natural sugars in whole fruit and plain milk are not the problem; whole fruit contains fibre, which slows absorption. Honey, brown sugar, palm sugar and syrups are still added sugar.

Absorption and bioavailability

Sugars are absorbed quickly. Glucose and galactose are taken up by the same transporter in the small intestine, and fructose by another and processed mainly in the liver. Liquid sugars and sugar eaten on its own raise blood glucose fastest; fibre, protein and fat in a meal slow it.

Connection to daily life

1. Dental health: how often you have sugar matters as much as how much — limit sipping and snacking on sweet things
2. Energy and sleep: sugary drinks can cause energy peaks and dips, and sugar late in the day may disturb sleep — see Sleep
3. Weight and blood sugar: cutting sweet drinks is one of the simplest changes with a large effect
4. Exercise: sugars can help fuel and refuel prolonged exercise, but most people do not need sports drinks — see Exercise

Sources: 1. National Academies of Sciences, Engineering, and Medicine — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) 2. HealthHub Singapore — Recommended Dietary Allowances: https://www.healthhub.sg/well-being-and-lifestyle/food-diet-and-nutrition/recommended_dietary_allowances 3. HealthHub Singapore — Dietary guidelines for adults: https://www.healthhub.sg/well-being-and-lifestyle/food-diet-and-nutrition/dietary_guidelines_adults 4. Health Promotion Board — Singapore Food Insights Database (SG FoodID): https://www.hpb.gov.sg/healthy-living/food-and-beverage/sgfoodid/ 5. FAO/INFOODS — Food composition tables and databases: https://www.fao.org/food-composition/tables-and-databases/en/