What a large French study found, and what it does and doesn't mean.
5 min read
A study of 101,257 adults linked 100 mL a day of sugary drinks, less than half a cup, to an 18% higher relative rate of cancer.
The 2019 study in The BMJ followed adults in France for a median of 5.1 years. For every extra 100 mL a day of sugary drinks, the relative rate of overall cancer was 18% higher and of breast cancer 22% higher. Sugary drinks here included 100% fruit juice. It's observational research, so it shows an association, not cause, and the authors say it needs to be repeated in other large studies.
AICR says regular sugary drinks are a cause of weight gain, and excess body fat causes at least 12 cancers. That's the indirect route, and it applies to soda, sweetened tea and coffee, energy drinks and juice cocktails.
The American Cancer Society recommends limiting sugar-sweetened beverages, and AICR recommends drinking mostly water and unsweetened drinks.
The BMJ study adds a second possibility: that the drinks themselves matter, beyond weight. That isn't settled, and the evidence isn't strong enough to say that the sugar in a drink directly causes cancer. What's well supported is that drinks are the easiest place in the day to cut sugar without losing a meal.
+18%
higher relative rate of overall cancer per extra 100 mL (about 3.4 oz) a day of sugary drinks
NutriNet-Santé, The BMJ, 2019
+22%
higher relative rate of breast cancer per extra 100 mL a day
NutriNet-Santé, The BMJ, 2019
101,257
adults in the study, 79% women, followed a median of 5.1 years
The BMJ, 2019
355 mL
in one 12-ounce can of soda, for scale
unit conversion
Sugar-sweetened beverages and 100% fruit juice. When the researchers looked at 100% fruit juice on its own, it was linked to a 12% higher relative rate of overall cancer per extra 100 mL a day, and other sugary drinks were linked to a higher rate too. Diet drinks showed no statistically significant link in this study, though the authors cautioned that the group drank relatively few of them, so that doesn't prove they're risk-free.
These are relative differences, not changes in anyone's actual chance. An 18% higher relative rate does not mean that someone with a 10% cancer risk now has a 28% risk. The findings also don't mean that a small glass of juice or soda will cause cancer.
A 2023 review of 42 articles covering 37 groups of people and about 4.5 million participants found that sugar-sweetened beverages were associated with higher rates of breast and colorectal cancer, and that 100% fruit juice was associated with overall cancer. The authors rated the evidence as low certainty and said the absolute effects were small.
Count every one of these on a typical day.
Soda and energy drinks
Including sports drinks and flavored waters with sugar.
Sweetened coffee and tea
Flavored lattes, sweet tea, bottled tea, and coffee creamers with sugar.
Juice
100% juice was included in the study and was linked on its own to a 12% higher relative rate of overall cancer per extra 100 mL a day. Whole fruit, which has fiber, is the better choice more often.
Smoothies and juice cocktails
Some store-bought smoothies contain substantial amounts of sugar, particularly those made with juice concentrates, syrups or sweetened ingredients. Check the nutrition label.
Serving sizes
A bottled drink may contain two servings. If you drink the whole bottle, double the sugar and calories on the label.
| Your drink | Step down to |
|---|---|
| Soda | Sparkling water with a squeeze of lime or a splash of juice |
| Sweet tea | Unsweetened iced tea with lemon, then cut the sugar in half each week |
| Sweetened coffee | Half the sweetener, then none; or a splash of milk and cinnamon |
| Juice | Whole fruit and a glass of water |
| Energy drinks | Cold black coffee or unsweetened tea, and check your sleep |
Myth
100% juice is as good as fruit.
What research says
Whole fruit has fiber and takes longer to eat. In the BMJ study, 100% fruit juice on its own was linked to a 12% higher relative rate of overall cancer, though one observational study can't show that juice is the cause. The American Cancer Society recommends whole fruits.
The BMJ, 2019; American Cancer Society
Myth
This study proves sugary drinks cause cancer.
What research says
It's an observational study, and the authors say it can't establish cause and needs to be replicated.
The BMJ, 2019
Myth
Diet drinks are a free pass.
What research says
The study found no statistically significant link for artificially sweetened drinks, but the participants drank few of them, so that doesn't prove they're risk-free. Water and unsweetened drinks are what AICR recommends.
The BMJ, 2019; AICR
Myth
A small glass of juice or soda will give you cancer.
What research says
The percentages in the study are relative differences across a population, not an individual's chance of cancer, and the study showed an association, not cause.
The BMJ, 2019
Audit one typical day
Write down every sugary drink, including juice and coffee drinks.
Replace one daily drink
Pick the one you have most days and swap it using the step-down table. Do it every day this week.
Keep the replacement close
Fill a bottle or pitcher and put it where the old drink lived.
Choose a second drink for next week
Move down your list until the sugary drinks are the exception.
- The BMJ: Sugary drink consumption and risk of cancer: results from the NutriNet-Santé prospective cohort (2019)
- International Journal of Behavioral Nutrition and Physical Activity: Association of soft drinks and 100% fruit juice consumption with risk of cancer: a systematic review and dose-response meta-analysis of prospective cohort studies (2023)
- American Institute for Cancer Research: Cancer prevention recommendations: sugary drinks
- American Cancer Society: Guideline for Diet and Physical Activity for Cancer Prevention