Plain tea is keto-friendly: black, green, white, oolong and herbal teas brewed with water have almost no carbohydrate. What changes the picture is what you add. A splash of milk adds about 1 to 1.5 g of carbs, a teaspoon of sugar adds about 4 g, and sweetened drinks such as bottled iced tea, chai lattes, matcha lattes and bubble tea can contain 20 g of sugar or more. Tea also contains caffeine: the FDA lists about 37 mg in a 12 oz cup of green tea and 71 mg in black tea, compared with a 400 mg daily limit for most adults.
Teas that fit keto
| Tea | Carbs per cup, plain | Notes |
|---|---|---|
| Black tea | 0 to 1 g | Contains caffeine |
| Green tea | 0 to 1 g | Contains caffeine; our guide to green tea benefits covers the evidence |
| White and oolong tea | 0 to 1 g | Contain caffeine |
| Herbal teas (peppermint, chamomile, rooibos, ginger) | 0 to 1 g | Usually caffeine-free |
| Fruit teas, unsweetened | 0 to 1 g | Check for added sugar or dried fruit pieces |
Plain brewed tea is mostly water, so it also counts toward your daily fluid intake.
What you add matters most
Per cup, calculated from USDA FoodData Central values:
| Addition | Amount | Carbs added |
|---|---|---|
| Semi-skimmed (2%) milk | 30 ml (a splash) | about 1.4 g |
| Whole milk | 30 ml | about 1.4 g |
| Heavy cream | 15 ml (1 tablespoon) | about 0.4 g |
| Unsweetened almond milk | 30 ml | about 0.1 g |
| Sugar | 1 teaspoon (4 g) | 4 g |
| Honey | 1 teaspoon (7 g) | about 6 g |
A cup of tea with a splash of milk and no sugar fits easily into keto, even several times a day. Two sugars in each of four cups a day would add 32 g of sugar, more than a strict keto allowance on their own. Our article on coffee on keto covers creamers and sweeteners in more detail.
Tea drinks to watch
- Bottled iced tea: a 500 ml bottle of sweetened green tea has about 27 g of sugar, based on USDA values. Choose unsweetened versions.
- Chai lattes: café chai is usually made from a sweetened concentrate with milk. Ask for unsweetened, or brew chai spices at home.
- Matcha lattes: a 250 ml latte made with semi-skimmed milk has about 12 g of carbohydrate from the milk alone, before any syrup. Make it with unsweetened almond or coconut milk to cut the carbs.
- Bubble tea: the tapioca pearls and sweetened milk make it one of the highest-sugar drinks you can order. It doesn’t fit keto.
- Kombucha: a fermented tea that contains some sugar. Check the label: carbs vary a lot between brands.
How to make keto iced tea at home
Homemade iced tea costs little and has no hidden sugar:
- Steep 4 tea bags, black, green or fruit, in 1 liter (about 4 cups) of just-boiled water for 4 to 5 minutes.
- Remove the bags and let the tea cool.
- Add lemon or lime slices, fresh mint or a few crushed berries for flavor.
- Sweeten lightly with stevia or monk fruit if you like.
- Chill and pour over ice. Keep it in the fridge and drink it within 2 to 3 days.
For a smoother taste, try cold brewing: put the tea bags in cold water and leave them in the fridge overnight.
Sweetening tea on keto
If you like your tea sweet, use stevia, monk fruit, erythritol or allulose, which don’t raise blood sugar. Our guide to sugar alcohols and sweeteners on keto compares them. Many people find their taste adjusts within a few weeks and they need less sweetener over time.
Caffeine on keto
Tea can help with the tiredness some people feel in the first weeks of keto, but watch the total caffeine from tea, coffee, energy drinks and pre-workout supplements. The FDA says 400 mg a day isn’t generally linked with harmful effects in healthy adults, and advises people who are pregnant or breastfeeding to talk to their healthcare provider. The NHS suggests avoiding tea and coffee for at least 6 hours before bed if you have trouble sleeping.
Herbal teas: a few cautions
Most herbal teas are safe in normal amounts. A few points:
- Pregnancy: the NHS suggests no more than 4 cups of herbal tea a day in pregnancy, and advises against liquorice root tea.
- Medicines: some herbs, such as St John’s wort, interact with medicines. Check with a pharmacist if you take regular medication.
- “Detox” and “slimming” teas often contain laxatives, which cause water loss rather than fat loss, and the FDA warns that some weight loss teas contain hidden drug ingredients.
Can tea help on keto?
Unsweetened tea is a useful zero-carb drink that adds flavor and variety to your day, which can make it easier to stick to keto. Green tea has a small effect on weight in some studies, as the NCCIH summarizes, but it isn’t a weight loss tool on its own. Its main value on keto is as a satisfying alternative to sugary drinks.
Common questions
Does tea break ketosis?
Plain tea doesn’t. Tea with a splash of milk or cream doesn’t either for most people. Sugar, honey and sweetened tea drinks can.
Is milk in tea keto?
A splash is fine: about 1.4 g of carbs per 30 ml. If you drink a lot of milky tea, use cream or unsweetened almond milk instead.
Can I drink tea on an empty stomach?
Yes, though strong black tea on an empty stomach upsets some people. If it does, have it with food.
Does tea dehydrate you?
No, not in normal amounts. Caffeine has a mild effect on urine output, but the water in the tea more than makes up for it. The NHS includes tea and coffee in the drinks that count toward your daily fluid intake, which matters on keto, when you lose more water in the first weeks.
Safety note: Keto isn’t suitable for everyone. If you have diabetes, kidney or liver disease, take regular medication, or are pregnant or breastfeeding, talk to your doctor before cutting carbs this far (why it matters).
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
