When You Eat Too Many Blueberries, This Is What Happens

Packed with antioxidants, blueberries offer both flavor and nutrition. A one-cup serving has just 84 calories and 3.6 grams of fiber, reports My Food Data. It also offers 16% of the recommended daily vitamin C intake, 24% of the recommended daily amount of vitamin K, and 22% of the recommended daily allowance of manganese. These tiny fruits are also rich in phenolic acids, quercetin, anthocyanidins, and other compounds with antioxidant activity (via the Journal of Zhejiang University Science B). The question is, what happens when you eat too many blueberries?

Most fruits, including blueberries, are relatively high in fiber. When consumed in excess, this nutrient may cause bloating, gas, diarrhea, and mineral deficiencies, warns Duke University. Generally, women should not exceed 25 grams of dietary fiber per day. Men, on the other hand, should aim for about 38 grams per day. While it's unlikely to get too much fiber from blueberries alone, you may feel bloated after eating three or four cups of berries — especially if you increase your fiber intake too quickly.

Even the healthiest foods can be harmful when consumed in large amounts. Blueberries are no exception. Here's what you should know about their potential side effects. 

Eating too many blueberries may cause weight gain and high blood sugar

Eating blueberries every day can make it easier to get more vitamins, minerals, and antioxidants into your diet — just make sure you don't go overboard. These dark-colored fruits boast over 21 grams of carbs, including 14.7 grams of sugar, per cup (via My Food Data). The same amount of strawberries, by comparison, contains 11 grams of carbs — including 7 grams of sugar in the form of fructose. Watermelon, oranges, and other fruits are much lower in sugar than blueberries, too.

If you eat three cups of blueberries per day, you'll get nearly 65 grams of carbs and 44 grams of sugars. This could lead to weight gain and hyperglycemia in the long run. "Fruit should not be totally avoided for this reason [its high sugar content], it just needs to be kept in reasonable portions and eaten alongside other foods," says dietician Jen Bruning (via Insider). The U.S. Department of Agriculture recommends about 1 ½ to 2 cups of fruits per day for adult women and 2 to 2½ cups per day for adult men. It's fine to overindulge from time to time, but try not to make a habit out of it. 

Blueberries can increase the risk of bleeding

As mentioned earlier, blueberries provide nearly 25% of the daily recommended intake of vitamin K per cup. This fat-soluble nutrient supports blood clotting and bone health, explains the Linus Pauling Institute. The problem is that it can interact with warfarin and other blood thinners, leading to an increased risk of bleeding. People who take blood thinners should not exceed the recommended daily amount of vitamin K, which is 90 micrograms for adult women and 120 micrograms for men. They also need to avoid large fluctuations in their vitamin K intake, says the Linus Pauling Institute.

Apart from that, eating too many blueberries is unlikely to cause major issues. These fruits, however, contain large amounts of salicylates, according to the Royal Berkshire Hospital. People who are sensitive or allergic to salicylates may experience rashes, diarrhea, stomach pain, hives, inflammation, and other adverse reactions after eating blueberries (via the Royal Berkshire Hospital and Healthline).

Salicylates occur naturally in a wide range of fruits, vegetables, and animal products, but this doesn't mean they're safe. If you're allergic or sensitive to these compounds, you may still be able to eat blueberries in small amounts. The Royal Berkshire Hospital recommends consuming high-salicylate foods along with fresh figs, apples, lemons, cabbage, dairy, grains, seeds, meat, fish, and other low-salicylate foods or beverages.