Zero calorie soft drinks: are diet colas a healthy swap?
A can of regular cola has about 9 teaspoons of sugar. The "diet" or "zero" version has almost none. So is switching a smart move, or just swapping one problem for another? The answer is somewhere in the middle.
Quick answer
- A 330 ml can of regular cola has about 35 g of sugar and 140 calories. The zero version has about 1 calorie.
- Zero drinks are sweetened with aspartame, acesulfame K, sucralose or stevia, which are approved as safe within daily limits.
- Swapping regular for zero can help cut sugar and calories. But the WHO advises against relying on sweeteners for long-term weight control.
- Zero drinks are still acidic (hard on teeth) and many have caffeine. Water, plain lassi and lemon water are better everyday drinks.
Regular vs zero: the numbers
| Drink | Size | Calories | Sugar |
|---|---|---|---|
| Regular cola | 330 ml can | 140 | 35 g (9 tsp) |
| Regular cola | 1.5 litre bottle | 630 | 160 g (40 tsp) |
| Diet / zero cola | 330 ml can | 1 | 0 g |
| Packet fruit juice | 250 ml | 110 to 130 | 25 to 30 g |
| Energy drink | 250 ml | 110 | 27 g |
| Water or soda water | Any | 0 | 0 g |
The WHO advises keeping added sugar to less than 10 percent of daily calories, and ideally under 5 percent, which is about 25 g (6 teaspoons) a day. One can of regular cola is already more than that.
What sweetens zero drinks?
Instead of sugar, zero drinks use very small amounts of high-intensity sweeteners. The most common are:
- Aspartame: about 200 times sweeter than sugar. Carries a warning for people with the rare condition phenylketonuria (PKU).
- Acesulfame K (Ace-K): about 200 times sweeter, often mixed with aspartame.
- Sucralose: about 600 times sweeter.
- Stevia: from a plant, used in some newer drinks. See stevia: is it safe and healthy?
Each one has an "acceptable daily intake" (ADI) set by expert food safety groups. For aspartame, it is 40 mg per kg of body weight a day. A 70 kg adult would need to drink about 9 to 14 cans of diet cola every day to reach that limit. For more on each type, read alternative sweeteners explained.
What about the aspartame cancer news?
In 2023, the International Agency for Research on Cancer (IARC) placed aspartame in its group "possibly carcinogenic to humans" (Group 2B), based on limited evidence. At the same time, the WHO and FAO expert committee (JECFA) reviewed the same evidence and kept the safe daily limit the same, at 40 mg per kg. In simple words: the evidence is not strong, and normal amounts are considered safe, but it is a reason not to drink large amounts every day.
Do zero drinks help with weight loss?
The research is mixed:
- Short term: swapping sugary drinks for zero ones cuts calories, and in some trials it helped people lose a little more weight.
- Long term: in 2023, the WHO reviewed all the studies and advised against using sweeteners as a main way to control weight. Long-term studies did not show clear benefits, and some found links with higher risk of type 2 diabetes and heart disease, though these studies cannot prove cause.
- Sweet habit: drinking very sweet drinks every day, even with no sugar, may keep your taste buds wanting sweet things.
So: zero is better than regular if you drink cola every day and are trying to break the habit. But water is better than both.
Other things to know
- Teeth: colas contain phosphoric and citric acid, which can wear away tooth enamel, with or without sugar. Use a straw, do not sip slowly over hours, and rinse with water after.
- Caffeine: a can of cola has about 30 to 45 mg. Late-night cola can disturb sleep, and it adds up with chai and coffee.
- Bones: some studies link a lot of cola with lower bone density in women, possibly because cola replaces milk in the diet.
- Children: zero drinks are not advised for young children. Water and milk are the best drinks for kids.
- Pregnancy: normal amounts of approved sweeteners are considered safe, but limit caffeine to 200 mg a day from all sources.
How to cut down on soft drinks
- Do not keep big bottles at home. A 1.5 litre bottle on the table gets finished.
- Step down: regular cola, then zero, then soda water with lemon, then plain water.
- Try fizzy water with lemon, mint or a slice of cucumber if you miss the bubbles.
- Choose desi drinks: plain or salty lassi, chaach, nimbu pani with little sugar, or green tea.
- At weddings and restaurants, ask for water or a zero drink instead of regular. See healthy eating at weddings.
Common questions
Is Coke Zero or Pepsi Max bad for you?
In normal amounts, a can now and then is considered safe for healthy adults. It is better than regular cola for sugar and calories, but water is the best everyday drink.
Does diet cola raise blood sugar?
No, not directly. The sweeteners used have little or no effect on blood sugar, so people with diabetes may use them instead of regular soft drinks.
How many diet drinks a day is too many?
There is no exact number, but most experts suggest no more than one or two a day. The acid and caffeine are also reasons to keep it low.
Do zero drinks cause belly fat?
They have almost no calories, so they do not add fat directly. Some studies link them to weight gain, but this may be because people who already have weight problems drink more of them.
Sources
- World Health Organization. Use of non-sugar sweeteners: WHO guideline. Geneva, 2023. www.who.int/publications/i/item/9789240073616
- World Health Organization. Aspartame hazard and risk assessment results released (IARC and JECFA), July 2023. www.who.int/news
- World Health Organization. Guideline: sugars intake for adults and children. Geneva, 2015. www.who.int/publications/i/item/9789241549028
- Rios-Leyvraz M, Montez J. Health effects of the use of non-sugar sweeteners: a systematic review and meta-analysis. World Health Organization, 2022. www.who.int/publications/i/item/9789240046429
- Tucker KL, Morita K, Qiao N, et al. Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: the Framingham Osteoporosis Study. American Journal of Clinical Nutrition, 2006;84:936-942. doi.org/10.1093/ajcn/84.4.936
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: cola, regular and diet. fdc.nal.usda.gov
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