4 Negative Effects of Eating Too Many Grapes

Unintended Weight Gain
If you sit down with a bag of grapes and turn on the TV, before you know it, you could eat most of the bag. Suddenly, your 62-calorie snack can multiply, eventually giving you the same number of calories you'd get if you ate a small meal. If you eat large portions of grapes on a regular basis without first measuring your portion size, the additional calories may cause you to gain unintended weight. As they say, everything in moderation, right?
Carb Overload
Gut-Related Concerns
Grapes offer some fiber — roughly 1 g from 1 cup. That's probably not enough to cause any disruption in your gut. If you snack on a larger serving of grapes, however, you increase your fiber intake.
Allergy Attack
An allergic reaction doesn't necessarily mean you're allergic to the fruit itself. You may be allergic to a pesticide on the grapes, or to the yeast or mold that grows on the grapes. The only way to be certain what you're allergic to is to undergo allergen testing at your physician's office or via a referral to a testing center. So if you’re experiencing symptoms after eating grapes, your best bet is to check in with a healthcare provider for proper testing before you consume more grapes.
The Takeaway
- Grapes are a nutritious and delicious fruit to snack on in moderation.
- Eating grapes to excess can lead to unwanted side effects, such as unintended weight gain, carb overload, and gastrointestinal symptoms related to their fiber content.
- Some people may have a grape allergy, which could make this fruit unsafe to eat.
- Grapes. U.S. Department of Agriculture.
- Dietary Guidelines for Americans 2020-2025. U.S. Department of Agriculture & U.S. Department of Health and Human Services. March 2021.
- Carbohydrates. MedlinePlus. March 25, 2024.
- Fiber. MedlinePlus. July 23, 2024.
- Anaphylaxis. Mayo Clinic. April 16, 2025.

Kara Andrew, RDN, LDN
Medical Reviewer
Kara Andrew, RDN, LDN, is the director of health promotion for Memorial Hospital in Carthage, Illinois. She is also licensed as an exercise physiologist and certified in lifestyle medicine by the American College of Lifestyle Medicine. Her experience includes corporate wellness, teaching for the American College of Sports Medicine, sports nutrition, weight management, integrative medicine, oncology support, and dialysis.
She earned her master's in exercise and nutrition science at Lipscomb University.
Andrew has served as a president and board member of the Nashville Academy of Nutrition and Dietetics. She was recently elected a co-chair of the fitness and medicine group in the American College of Lifestyle Medicine.

Melodie Anne
Author
Melodie Anne Coffman specializes in overall wellness, with particular interests in women's health and personal defense. She holds a master's degree in food science and human nutrition and is a certified instructor through the NRA. Coffman is pursuing her personal trainer certification in 2015.