Sweet iced tea or coffee every day: how much sugar is that?

One Thai study found that a single sweet iced tea or coffee can hold more sugar than a whole day's guide. In a lab analysis of drinks sold around Mahidol University's Salaya campus, Sridonpai and colleagues found that iced Thai milk tea averaged 20.5 g of sugar per 100 mL, which they estimated at about 8 to 16 teaspoons for a cup as sold. A guide in Ramathibodi Hospital's @Rama magazine puts the limit at 4 to 8 teaspoons of sugar a day, depending on how much energy you use. You do not have to give up the drink: asking for less sugar, choosing a smaller cup and drinking water for the rest of the day all bring the total down.

How much sugar is in a cup of iced Thai tea or coffee?

What a Thai lab analysis found

Between July and August 2016, researchers from Mahidol University's Institute of Nutrition surveyed drink shops and stalls on and within 500 metres of the Salaya campus, collected the most popular drinks from 60 of them, and measured their sugar in the laboratory. The five most popular drinks were iced Thai milk tea, cocoa, milk green tea, coffee and chrysanthemum drink. The study was published in 2019.

The teaspoon figures are the researchers' own estimates. They assumed that in an iced drink about a third of the cup is drink and the rest is ice, and that 1 teaspoon of sugar weighs 4 g.

Why one cup holds so much

• Bigger cups. The researchers noted that cup sizes had grown, from a largest size of about 660 mL to 960 mL.
• Bitter bases. Tea, coffee and cocoa are bitter, so shops add sugar, condensed milk or syrup to taste. Cocoa varied the most between shops, by 22 g per 100 mL.
• Every drink was sweet. None of the drinks tested had 6 g of sugar per 100 mL or less, the level the study cites for the Healthier Choice logo on drinks.

The study covered one area and was a snapshot, so drinks elsewhere may differ.

Bottled drinks from the supermarket

Across the two Thai studies, the bottled drinks had less sugar per 100 mL than the shop-made iced drinks, though the studies were done in different years and places, and a whole bottle still adds up. A 2025 study by Nguyen Ngoc and colleagues recorded 881 bottled and packaged drinks in a major Bangkok supermarket in 2022. The median sugar content was 5.0 g per 100 mL, 27.7% carried the Healthier Choice logo and had less sugar, and 40.1% contained at least one low- or no-calorie sweetener. The authors found that drinking a typical bottle sweetened with sugar in one go often went over the WHO's recommended daily limit of 5% of energy from free sugars.

How much sugar a day is the limit?

Amounts by energy needs (@Rama magazine)

The @Rama guide, written by a nutrition lecturer at Mahidol University's Faculty of Public Health, links the daily sugar limit to how much energy a person needs.

The guide counts all kinds of sugar added to food and drinks, including white sugar, brown sugar, honey and syrups. It also suggests choosing water instead of sweet drinks and checking the nutrition label: if a product has more than 15 g of sugar (3 teaspoons), avoid it.

UK and US guidance

• England. The NHS says adults should have no more than 30 g of free sugars a day, roughly 7 sugar cubes. Free sugars are sugars added to food or drinks, plus the sugars in honey, syrups, and unsweetened fruit juices, vegetable juices and smoothies.
• United States. The CDC says the US Dietary Guidelines recommend that adolescents and adults have no more than 10 g of added sugars per meal.

The study's estimate for one cup of iced Thai milk tea, 8 to 16 teaspoons, is equal to or more than the 4 to 8 teaspoons a day in the @Rama guide.

How common are daily sweet drinks among Thai people?

University students

• In a study of 280 university students aged 18 to 22 in southern Thailand, Petchoo and colleagues found that 79.2% ate and drank more added sugar than the WHO recommends, and that drinks made up the largest share of that sugar, 46.5%. The study used a 24-hour diet recall.
• In a 2025 study of 387 students aged 19 to 22, Pouyfung and colleagues found that sweetened tea was the most frequently consumed sugary drink, especially freshly made iced milk tea.

Office workers

In a study of 337 office workers in a semi-urban area of southern Thailand during the COVID-19 period, Pouyfung and colleagues found that milk tea, such as Thai tea and green tea, was the most consumed sugary drink, and that 70.6% of the workers had more than 24 g of sugar a day, above the WHO recommendation.

The tax on sugary drinks

Thailand has had an excise tax on sugar-sweetened drinks since September 2017. Following 5,594 people in 2018 and 2019, Phulkerd and colleagues at Mahidol University found that consumption of taxed sugary drinks fell more than consumption of untaxed ones.

What these studies can and cannot tell us

These studies describe groups of people in particular places, such as students in the south or workers in one area, and most relied on people recalling what they ate and drank. They show how common sweet drinks are, not what happens to any one person. For national survey figures on what Thai people eat, see What do Thai people eat, according to national surveys?

I don't want to give up my daily iced drink. What can I change?

When you order

• Ask for less sugar or no sugar. The Thai lab study notes that shops add sugar to suit the customer's taste, so the sugar in a shop-made cup depends on each shop's recipe and on what you ask for.
• Choose the smaller cup. In the Thai study, the same drink in a bigger cup carried several more teaspoons.
• The CDC suggests skipping flavoured syrups and whipped cream at the coffee shop, and choosing unsweetened tea or coffee.
• Try a plain black coffee or unsweetened tea some days. The Americano in the Thai study was sweet because sugar was added, not because of the coffee.

Across the day

• Treat the iced drink as one part of the day's sugar, not on top of sweet snacks and other sweet drinks.
• Carry a water bottle and refill it, as the CDC suggests. Adding slices of lime, lemon or cucumber gives plain water some flavour.
• If you buy bottled drinks, read the label. In the Bangkok supermarket study, drinks with the Healthier Choice logo had less sugar, though more of them used sweeteners. The @Rama guide's rule of thumb is to avoid products with more than 15 g of sugar.

Getting used to less sweetness

The NHS suggests that if you take sugar in hot drinks, you gradually reduce the amount until you can cut it out altogether, or switch to a sweetener. Stepping down from regular sweetness to less sweet, then to a little sweet, is one way to do this with iced drinks.

For mornings when a sweet coffee stands in for breakfast, see No time for breakfast before work. What can I eat?

What about fruit juice, smoothies and drinks with milk?

Juice and smoothies

The NHS counts the sugars in unsweetened fruit juice, vegetable juice and smoothies as free sugars, even though they occur naturally. It advises no more than 150 mL of these drinks a day in total, a small glass. In the Thai study, orange juice from shops had 11.3 g of sugar per 100 mL and some fruit drinks had sugar added on top.

Milk and whole fruit

The NHS says the sugar found naturally in milk, fruit and vegetables does not count as free sugars, though it is included in the "total sugars" figure on a label. Plain milk or unsweetened soy milk instead of a sweetened milk drink, and a piece of fruit instead of a sweet drink, are swaps that keep the taste of milk or fruit.

Do sweet drinks count towards my fluids for the day?

They do count, but they are not the best choice. The NHS recommends 6 to 8 glasses of fluid a day and says all non-alcoholic drinks count, but water, lower-fat milk and lower-sugar drinks, including tea and coffee, are healthier choices. It advises drinking more in hot weather or while exercising.

In the Thai heat it is easy to reach for a sweet iced drink every time you feel thirsty. Keeping water as the main drink and the sweet drink as a single cup makes the difference. For coping with the heat itself, see Drained and off your food in hot weather? What can I do?

If you are buying drinks for children, the NHS sets lower limits for children than for adults. See My child drinks sweet drinks every day. What should I do?