The short answer: Sugar is the part of your diet that matters most for tooth decay, and how often you have it matters as much as how much. Keep sweet foods and drinks to mealtimes, drink water in between, and go easy on soda and juice, which also wear away enamel. Cheese, plain yogurt, vegetables and nuts make better snacks, though no single food has strong evidence of protecting teeth.
What you eat affects your teeth mostly through what happens in your mouth. Plaque bacteria turn sugars into acid that causes tooth decay, and acidic foods and drinks can dissolve enamel directly, a process called erosion (Moynihan & Petersen, 2004). Diet matters for your gums too, although fewer studies have looked at that (American Dental Association, 2023). This guide covers how much sugar matters, which drinks are hardest on teeth, which foods may help, when to brush and which nutrients matter for your gums, including where the evidence is thin.
Prefer to watch? Here is this article as an 8-minute video.
More short videos: see them all on our Videos page or subscribe on YouTube.
How much sugar is bad for your teeth?
How much: the WHO limit
The World Health Organization (WHO) recommends that adults and children keep free sugars below 10% of their daily energy intake. It suggests a further cut to below 5%, or roughly 25 grams (6 teaspoons) a day, for additional benefit (World Health Organization, 2015).
Free sugars are sugars added to foods and drinks, plus the sugars in honey, syrups and fruit juices; sugars in whole fresh fruit, vegetables and milk don’t count. Much of it is hidden: a single can of sugar-sweetened soda can contain up to 40 grams (around 10 teaspoons) (World Health Organization, 2015).
The guideline’s dental evidence comes from a systematic review by Moynihan and Kelly. Of the 55 studies included, 42 of 50 in children and all 5 in adults found at least one link between more sugar and more decay. Evidence that cavities are less common below 10% of energy was rated moderate quality; for the 5% target, it was very low quality (Moynihan & Kelly, 2014).
How often: why grazing is hard on teeth
Each time you have something sugary, plaque bacteria make acid for a while afterward, so sipping and snacking all day means more acid attacks. A review from a WHO collaborating center rated the evidence linking both the amount and the frequency of sugar to decay as convincing, and advised having sugary foods and drinks no more than four times a day (Moynihan & Petersen, 2004).
Some researchers think frequency, including snacking between meals, predicts cavity risk better than the total amount, but that is still a hypothesis (American Dental Association, 2023). A systematic review of five cohort studies in children found that eating processed sugary and starchy foods between meals was consistently linked with more cavities, while findings for total intake were mixed (Hancock et al., 2020).
Which drinks are worst for your teeth?
Drinks make it easy to have a lot of sugar, often. In a systematic review of 38 studies, people who drank more sugar-sweetened beverages had more cavities and more enamel erosion, and heavy drinkers had about three times the odds of erosion compared with moderate drinkers (Valenzuela et al., 2021). The studies were cross-sectional, so they can’t prove cause, but the dose-response pattern suggests the link is likely causal.
Acid is a separate problem. Erosion happens when acid dissolves enamel directly, without help from bacteria. In a 2024 meta-analysis, eating acidic foods was linked with more than twice the odds of erosive tooth wear (odds ratio 2.40, 95% CI 1.44 to 4.00), and carbonated drinks with 43% higher odds (Marschner et al., 2024). How often you have acidic drinks and how long they stay on your teeth both matter (American Dental Association, 2023).
Fruit juice is a double hit: its sugars count as free sugars (World Health Organization, 2015), and in children and teens, acidic fruit juices, carbonated drinks and acidic sweets were all linked with more erosion (Salas et al., 2015). Sugar-free doesn’t mean acid-free: diet sodas are carbonated too, and carbonated drinks are linked with erosion (Marschner et al., 2024). For your daily cup, see how coffee affects your teeth.
What foods are good for your teeth?
No food cancels out sugar. The American Dental Association notes that dairy, apples, cranberries, tea and high-fiber foods have been suggested to help prevent decay, but that this needs more careful study (American Dental Association, 2023).
Cheese, milk and plain yogurt
Cheese has the most direct evidence. In plaque pH studies, eating cheese after a sugary snack almost completely prevented the usual drop in plaque pH, and cheese also stimulates saliva and raises calcium levels in plaque (Moynihan & Petersen, 2004). These are short-term measurements of plaque acidity, not long-term trials that count cavities.
Milk does not appear to raise cavity risk and may lower it (American Dental Association, 2023). In a meta-analysis of 13 studies of 8- to 19-year-olds, drinking more milk and eating more yogurt were linked with less erosion (Salas et al., 2015). Choose plain versions, because the sugars added to flavored milk and sweetened yogurt count as free sugars (World Health Organization, 2015).
Crunchy vegetables, fruit and fiber
Chewing fibrous foods stimulates saliva, which is thought to be the main way they protect teeth (Moynihan & Petersen, 2004). Raw carrots, celery and cucumber are also low-sugar snacks. Just don’t count on them to clean your teeth: the ADA says their suggested benefits still need careful study (American Dental Association, 2023).
Whole fresh fruit appears to be low risk for cavities, and citrus fruits have not been linked with decay (Moynihan & Petersen, 2004). The concern with citrus is acid, so enjoy it with a meal rather than sipping lemon water all day. Read more about the role of saliva in protecting your teeth.
Water and nuts
Plain water is the best drink between meals because it has no sugar and no acid. Plain nuts and seeds are low in sugar, so a handful makes a better snack than cookies or crackers. Their main benefit for your teeth is what they replace.
Are starchy and sticky snacks bad for your teeth?
Starch is less harmful than sugar. Table sugar and its building blocks, glucose and fructose, are broken down by plaque bacteria faster than starches and cause a sharper drop in pH (American Dental Association, 2023).
A systematic review done to inform WHO guidance found low-quality evidence that total starch intake is not linked with cavities, but that rapidly digested starches, typically refined ones such as white bread and crackers, may raise the risk (Halvorsrud et al., 2019). Processed sugary or starchy snacks are the ones to watch: in children, eating them between meals was consistently linked with more decay (Hancock et al., 2020).
Sticky or slowly eaten sweets, like hard candies, lollipops and caramels, turn one sugar hit into a long one. If you want a treat, have it with or right after a meal.
Is xylitol good for your teeth?
Swapping a sugary drink or snack for a sugar-free version cuts the sugar your teeth are exposed to. Xylitol, a sugar alcohol used in gum, mints and some toothpastes, is often marketed as actively fighting decay, but the evidence for that is modest.
A Cochrane review of 10 trials found low-quality evidence that fluoride toothpaste containing 10% xylitol may reduce cavities in children’s permanent teeth by 13% over about three years, compared with fluoride-only toothpaste. For other xylitol products, and for adults, the evidence was too weak to say whether they help. Side effects reported in the trials included bloating, gas and loose stools (Riley et al., 2015).
The ADA describes the overall findings on sugar alcohols such as xylitol as equivocal and has no policy on using xylitol to prevent cavities (American Dental Association, 2023). Sugar-free gum is a better-supported option because chewing it increases saliva flow (American Dental Association, 2023), and any sugar-free gum will do. One observational study has also linked high blood xylitol levels to heart attack and stroke, which needs more research (Witkowski et al., 2024). For more, see the benefits and risks of chewing gum.
When should you eat, snack and brush?
Because frequency matters, when you eat counts as well as what you eat. Aim for regular meals and a few planned snacks rather than grazing:
- Have sweet foods and drinks with meals, not on their own in between.
- Drink water between meals instead of juice, soda or sweetened coffee and tea.
- Have sugary or acidic drinks with a meal rather than sipping them for hours.
- End a meal with a piece of cheese if you like; it blunts the acid drop that follows sugar (Moynihan & Petersen, 2004).
Should you wait to brush after acidic food?
A common tip is to wait up to an hour after acidic food or drink before brushing, because acid-softened enamel might wear away more easily. A 2024 scoping review of 17 studies found that most of the evidence, largely from enamel samples worn in volunteers’ mouths, showed that brushing with fluoride toothpaste does not increase erosive wear, whenever it is done. The authors concluded that brushing right after an acid exposure can be recommended, though strong clinical trials are lacking (Fernández et al., 2024).
The ADA still advises waiting an hour after acidic food or drink so saliva can wash the acid away, and rinsing with water, drinking milk or eating cheese in the meantime (American Dental Association, n.d.). Waiting is reasonable, but if it means you would skip brushing altogether, brush gently with fluoride toothpaste instead, and focus on having acidic drinks less often. For the rest of your routine, see your daily dental hygiene routine.
Which nutrients help keep gums healthy?
Vitamin C has the clearest link to gum health. In a systematic review of 15 clinical trials with 1,140 mostly healthy participants, vitamin C supplements reduced gum bleeding in people whose blood levels of vitamin C were low, but had no clear effect in people whose levels were higher or unknown (Hujoel et al., 2021). Oranges, kiwi, strawberries, bell peppers and broccoli are all good food sources.
For other nutrients, the evidence is thin. Systematic reviews found insufficient evidence linking dietary minerals or fats to gum disease (American Dental Association, 2023), and very low-quality evidence suggests whole-grain starches may protect against it (Halvorsrud et al., 2019). Unless a doctor finds you are low in a nutrient, a varied diet is a better bet than supplements. If your gums bleed when you brush, read about gum disease and bleeding gums.
What are some easy swaps for healthier teeth?
Small changes you repeat every day add up:
| Instead of | Try |
|---|---|
| Soda, sweet tea or juice between meals | Water, with other drinks saved for mealtimes |
| A glass of fruit juice | A piece of whole fruit |
| Cookies, crackers or chips as a snack | Cheese, plain yogurt, raw vegetables or plain nuts |
| Hard candies or mints through the day | Sugar-free gum after meals |
| Dessert as a separate snack later | Dessert right after a meal |
| Lemon water sipped all day | Plain water, with citrus as part of a meal |
What it means for you
If you sip soda, juice or sweet coffee all day
Frequent sips mean frequent acid attacks. Have these drinks with meals and drink water in between (Moynihan & Petersen, 2004; American Dental Association, 2023). Our article on coffee and your teeth covers your daily cup.
If you snack a lot
Processed sugary and starchy snacks between meals were consistently linked with more decay in children (Hancock et al., 2020). Swap some of them for cheese, plain yogurt or raw vegetables, and keep sweets for mealtimes.
If you have reflux or vomit often
Regurgitation more than doubled the odds of erosive tooth wear in a large meta-analysis (Marschner et al., 2024). Get the medical cause treated, and ask your dentist to check your enamel.
If you pack snacks for kids
Keep juice small and sugary snacks occasional; our parent’s guide to kids’ teeth has age-by-age advice. Whole fruit counts as low risk for cavities (Moynihan & Petersen, 2004).
Questions to ask your dentist
- Do you see any signs of enamel erosion or early decay?
- Is my cavity risk high enough to need extra fluoride?
- Which of my usual drinks or snacks are hardest on my teeth?
- Should I wait before brushing after acidic food or drink?
- Could reflux or dry mouth be affecting my teeth?
When to see a dentist
Diet changes can’t undo damage that has already happened. Book a dental visit if you notice:
- Teeth that are newly sensitive to hot, cold or sweet foods (see why teeth become sensitive)
- Toothache, or dark spots or holes in your teeth
- Front teeth that look thinner, more yellow or see-through at the edges, which can be a sign of enamel wear
- Gums that bleed, look swollen or seem to be pulling back
- Frequent heartburn, reflux or vomiting; regurgitation more than doubled the odds of erosive tooth wear in a large meta-analysis (Marschner et al., 2024)
- A mouth that feels dry most of the time
Your dentist can also assess your cavity risk and tell you whether extra fluoride makes sense for you. For toothache with swelling or other urgent problems, see what to do in a dental emergency.
The bottom line
The most useful change you can make for your teeth is to have sugar less often and in smaller amounts, ideally at mealtimes. Limit acidic drinks, make water your default and choose snacks like cheese, plain yogurt, vegetables and nuts. No food replaces brushing twice a day with fluoride toothpaste.
References
American Dental Association. (2023). Nutrition and oral health. https://www.ada.org/resources/ada-library/oral-health-topics/nutrition-and-oral-health
American Dental Association. (n.d.). Dietary acids and your teeth. MouthHealthy. https://www.mouthhealthy.org/all-topics-a-z/dietary-acids-and-your-teeth/
Fernández CE, Silva-Acevedo CA, Padilla-Orellana F, Zero D, Carvalho TS, Lussi A. (2024). Should we wait to brush our teeth? A scoping review regarding dental caries and erosive tooth wear. Caries Research, 58(4), 454–468. https://doi.org/10.1159/000538862
Halvorsrud K, Lewney J, Craig D, Moynihan PJ. (2019). Effects of starch on oral health: Systematic review to inform WHO guideline. Journal of Dental Research, 98(1), 46–53. https://doi.org/10.1177/0022034518788283
Hancock S, Zinn C, Schofield G. (2020). The consumption of processed sugar- and starch-containing foods, and dental caries: A systematic review. European Journal of Oral Sciences, 128(6), 467–475. https://doi.org/10.1111/eos.12743
Hujoel PP, Kato T, Hujoel IA, Hujoel MLA. (2021). Bleeding tendency and ascorbic acid requirements: Systematic review and meta-analysis of clinical trials. Nutrition Reviews, 79(9), 964–975. https://doi.org/10.1093/nutrit/nuaa115
Marschner F, Kanzow P, Wiegand A. (2024). Anamnestic risk factors for erosive tooth wear: Systematic review, mapping, and meta-analysis. Journal of Dentistry, 144, 104962. https://doi.org/10.1016/j.jdent.2024.104962
Moynihan P, Petersen PE. (2004). Diet, nutrition and the prevention of dental diseases. Public Health Nutrition, 7(1A), 201–226. https://doi.org/10.1079/phn2003589
Moynihan PJ, Kelly SA. (2014). Effect on caries of restricting sugars intake: Systematic review to inform WHO guidelines. Journal of Dental Research, 93(1), 8–18. https://doi.org/10.1177/0022034513508954
Riley P, Moore D, Ahmed F, Sharif MO, Worthington HV. (2015). Xylitol-containing products for preventing dental caries in children and adults. Cochrane Database of Systematic Reviews, 2015(3), CD010743. https://doi.org/10.1002/14651858.CD010743.pub2
Salas MM, Nascimento GG, Vargas-Ferreira F, Tarquinio SB, Huysmans MC, Demarco FF. (2015). Diet influenced tooth erosion prevalence in children and adolescents: Results of a meta-analysis and meta-regression. Journal of Dentistry, 43(8), 865–875. https://doi.org/10.1016/j.jdent.2015.05.012
Valenzuela MJ, Waterhouse B, Aggarwal VR, Bloor K, Doran T. (2021). Effect of sugar-sweetened beverages on oral health: A systematic review and meta-analysis. European Journal of Public Health, 31(1), 122–129. https://doi.org/10.1093/eurpub/ckaa147
Witkowski M, Nemet I, Li XS, Wilcox J, Ferrell M, Alamri H, et al. (2024). Xylitol is prothrombotic and associated with cardiovascular risk. European Heart Journal, 45(27), 2439–2452. https://doi.org/10.1093/eurheartj/ehae244
World Health Organization. (2015). WHO calls on countries to reduce sugars intake among adults and children. https://www.who.int/news/item/04-03-2015-who-calls-on-countries-to-reduce-sugars-intake-among-adults-and-children
References checked October 2026 · Editorial policy · Report a correction
Discover more from HappyTeeth.Care
One email a month with new guides and one study, explained. Join and get a free printable dental emergency card. No spam, unsubscribe any time.
