Nuts are often praised as one of the best snacks you can eat, as they are packed with protein, fiber, healthy fats, vitamins, and minerals. They’re known to support heart health, lower cholesterol, and even aid weight management. But experts say that eating too many can lead to some unexpected side effects.
Jerlyn Jones, R.D.N., spokesperson for the Academy of Nutrition and Dietetics, says nuts should absolutely be part of your diet, but in moderation. “The benefits of nuts definitely outweigh any other drawbacks or cons”, she says. Here, we’ll look at what can happen when you overdo it, and how to enjoy nuts the healthy way.
The side effects of eating too many nuts
Most people underestimate how quickly the calories and fat from nuts can add up. Jones says a small handful, or about a quarter cup, is a good serving size for most adults. Beyond that, a few health issues can start to pop up.
You could gain weight instead of losing it
Nuts can help with weight control because they keep you full, but the catch is that they’re extremely calorie-dense. For example, a single ounce of almonds—about 23 nuts—has around 160 calories. Double that portion, and you’ve added 320 calories before you know it.
Jones explains that this can easily lead to weight gain if you don’t adjust your other meals or snacks to balance it out. “You want to be mindful of how many nuts you’re eating per day”, she says. While those calories come from healthy fats, they still count toward your total intake. Make sure to portion them out ahead of time or use them to enhance meals, like sprinkling almonds on a salad or adding walnuts to oatmeal.
You might experience digestive issues
If you’ve ever felt bloated or gassy after snacking on nuts, it’s not your imagination. According to Alan R. Gaby, M.D., nuts contain natural compounds like phytates and tannins that can make them harder to digest. Eating too many in one sitting can overwhelm your digestive system and lead to discomfort.
Nuts are also high in fat, which can speed up digestion for some people and cause diarrhea if eaten in large amounts. To minimize this, stick to smaller servings or try sprouted nuts; they’ve already started germinating, making them easier for the body to process. You can find sprouted versions of almonds, cashews, and other nuts at most health food stores.
Too many Brazil nuts can cause selenium overload
Brazil nuts deserve special attention. They’re an excellent source of selenium, a mineral that supports thyroid and immune function. The problem is that just six to eight of these provide almost ten times the recommended daily amount.
The National Institutes of Health warns that consistently eating too much selenium can cause symptoms like brittle nails, muscle pain, fatigue, and nerve problems over time. That’s why Jones advises keeping your serving small, ideally no more than four Brazil nuts a day, or every other day if you eat other selenium-rich foods.