Quick Answers
Eating too many vegetables is very unlikely to cause harm. Vegetables are packed with nutrients and fiber, which provide many health benefits. Eating a variety of vegetables as part of a balanced diet is recommended. However, eating extremely large amounts of certain raw vegetables or vegetable juices could potentially cause problems from ingesting too many antioxidants, vitamins, or fiber. Issues are more likely with juicing rather than whole vegetables. Moderation is key.
Could Eating Too Many Vegetables Be Unhealthy?
Vegetables are incredibly nutrient-dense and provide a host of health benefits. They are packed with vitamins, minerals, antioxidants, and fiber yet very low in calories. Consuming a diet high in vegetables has been linked to a reduced risk of many chronic diseases including heart disease, diabetes, and several cancers. Most health organizations around the world recommend eating a minimum of 3-5 servings of vegetables per day as part of a healthy, balanced diet. However, some people wonder if there could be any downsides to eating large quantities of vegetables. This article examines the evidence-based health effects of consuming too many vegetables.
Nutrient Overdose
In general, it is extremely difficult to overconsume most nutrients from vegetable sources. While animal products like meat and dairy are high in fat and contain cholesterol, plant foods like fruits and vegetables are naturally low in fat and calories. They are also cholesterol-free. Overconsuming certain vitamins and minerals like vitamin A, zinc, iron, and calcium can potentially cause harm. However, you would have to eat enormous and unrealistic quantities of vegetables to reach excessive intakes from food sources alone. For example, carrots are rich in beta-carotene, which your body converts into vitamin A. Yet you would have to eat over 100 cups of chopped carrots in a day to exceed the safe upper limit for vitamin A intake (1). Spinach is high in iron, yet you would have to eat around 90 cups (700 grams) of cooked spinach in one sitting to surpass the safe limit for iron (2). Furthermore, nutrients from vegetables come in a natural matrix alongside other beneficial compounds like antioxidants and fiber, which may actually reduce your body’s ability to absorb some of them (3).
Too Much Fiber
Eating large quantities of vegetables, especially raw vegetables or vegetable juice, could theoretically lead to digestive issues due to their fiber content. Soluble fiber helps feed beneficial gut bacteria but too much too quickly can cause gas, bloating, and diarrhea. These symptoms are more likely to occur if you suddenly increase your fiber intake by a large amount. One review found that increasing fiber intake by more than 5–10 grams per day often resulted in intestinal gas and bloating (4). Another study found that drinking 1 quart (946 ml) of high-fiber carrot juice per day for three weeks resulted in significantly more days with diarrhea compared to drinking 1 quart of low-fiber apple juice (5).
Goitrogens in Cruciferous Vegetables
Goitrogens are compounds found naturally in cruciferous vegetables like broccoli, cauliflower, cabbage, kale, and Brussels sprouts. When consumed in large amounts, goitrogens may interfere with proper thyroid gland function by blocking iodine absorption and causing goiter. Yet this is very unlikely to occur from eating reasonable amounts of cruciferous vegetables unless you have an iodine deficiency. One small study in 7 people found that 900 grams per day (about 4 cups) of raw bok choy lowered thyroid hormone levels by 20% after just one week (6). Another study found that 500 grams per day (about 2 cups) of raw Brussels sprouts for 4 weeks reduced thyroid hormone levels by 19% in healthy individuals (7). As long as you don’t have thyroid problems and your iodine status is adequate, there should be no concern with eating cruciferous vegetables as part of a healthy diet.
Too Many Antioxidants
Antioxidants are compounds in plant foods that help counter oxidative stress in your body by neutralizing unstable molecules called free radicals. Vegetables are excellent sources of antioxidants like carotenoids, polyphenols, and vitamin C. Diets rich in antioxidants have been linked to numerous health benefits, including reduced inflammation and lower rates of chronic diseases like heart disease and certain cancers (8). Yet some people worry whether getting too many antioxidants from your diet is harmful. Vegetables with deep color like sweet potatoes, carrots, spinach, kale, and broccoli are especially high in carotenoid antioxidants like beta-carotene. Several studies have shown that taking antioxidant supplements like vitamin E or beta-carotene long-term can actually increase disease risk and mortality (9, 10, 11, 12). However, there is no evidence that getting antioxidants from whole foods has the same effects. In fact, observational studies consistently link higher vegetable intake with health and longevity (13, 14). This may be because antioxidants from food work synergistically with the thousands of other beneficial compounds, which outweigh any potentially deleterious effects from isolated antioxidants.
Possible Benefits of Very High Vegetable Intake
Some evidence suggests that consuming even more vegetables than recommended could potentially offer additional health benefits.
Lower Disease Risk
Observational studies link diets very high in vegetables with better health and reduced risks of chronic diseases. For example, one extensive review linked consuming 7 or more daily servings to a 52% lower risk of death from heart disease and a 15% lower risk of death from cancer (15). Another large study in over 450,000 people found that eating 10 or more servings of vegetables and fruit per day was associated with a 24% lower risk of heart disease compared to eating less than 1.5 servings per day (16). What’s more, high vegetable intake has been linked to increased longevity. One study followed 65,000 vegetarians for over 15 years and found that those consuming at least 7 servings of fresh vegetables daily had a 52% lower risk of dying during the study period compared to those eating less than 1 serving per day (17). However, these studies are observational and cannot prove cause and effect. Plus, individuals who eat particularly high amounts of vegetables tend to be more health-conscious overall, which may further contribute to these findings.
Support Weight Loss
Several studies suggest that eating higher amounts of low-calorie, nutrient-dense vegetables may promote weight loss. Vegetables are high in water and fiber, which can help you feel fuller on fewer calories (18, 19). Increasing vegetable intake has been linked to reduced calorie intake and significant weight loss, even without intentional calorie restriction (20, 21). One study in 133 people with obesity found that simply doubling vegetable intake to 10 servings per day resulted in an average weight loss of 4.3 pounds (2 kg) over 12 weeks — without any other diet or lifestyle changes (22). Another study assigned 34 women to eat either 3 or 5 daily servings of vegetables. After 6 months, the 5-serving group lost an average of 2 pounds (0.9 kg) more than the 3-serving group — despite no other diet interventions (23). However, not all studies agree that a diet very high in vegetables promotes more weight loss than a diet moderately high in vegetables. One 12-week study found similar weight loss in participants assigned to eat either 7 servings or 12 servings of vegetables per day (24). Overall, vegetables are nutrient-dense, low in calories, and can help displace other higher calorie foods from your diet. That being said, simply aiming for the minimum recommended 5 servings of vegetables per day appears to offer the most benefit for the fewest calories.
Possible Downsides to Excessive Vegetable Juicing
Drinking vegetable juice can be a convenient way to increase your vegetable intake. However, there are some potential drawbacks to vegetable juicing that are important to consider.
High in Sugar and Low in Fiber
Juicing vegetables extracts the liquid but leaves behind most of the pulp and fiber. For example, 120 ml (4 ounces) of carrot juice provides around 5 grams of sugar but less than 1 gram of fiber (25). For comparison, a whole medium boiled carrot contains 4 grams of sugar alongside 3 grams of fiber (26). The same is true for greens like spinach and kale. Juicing them removes their fiber, an essential part of what makes vegetables so healthy. When consumed in liquid form without fiber, the natural sugars in juice are absorbed very quickly into your bloodstream. Large amounts of fruit juice have been linked to tooth decay, poor blood sugar control, and obesity (27).
Loss of Beneficial Compounds
Some vitamins, plant compounds, and minerals are degraded when vegetables are juiced. For example, juicing results in 12–59% lower polyphenol antioxidant content compared to raw vegetable consumption (28, 29). Carotenoid antioxidants can also be reduced by 5–13% during juicing. One study found that the stability of these antioxidants was largely dependent on the juice production method (30). Overall, more research is needed comparing health outcomes of juice versus whole vegetable intake. However, current evidence suggests that the beneficial compounds in vegetables may be better preserved through eating them whole.
High Doses of Vitamins and Minerals
The concentration and bioavailability of some vitamins, minerals, and antioxidants may be substantially higher in fresh vegetable juice compared to whole vegetables. While this might be beneficial for some people, it could also increase your risk of adverse effects when consumed in excess. For example, one study found that while a serving of whole carrots provided 417% of the RDI for vitamin A, one serving of fresh carrot juice provided 1,045% of the RDI for vitamin A (31). Drinking too much vegetable juice could potentially lead to excess intake of fat-soluble vitamins and minerals. Furthermore, juice made from raw vegetables retains more fat-soluble vitamins compared to juice that has been pasteurized for storage, which may increase your risk of adverse effects. Overall, moderation is key when consuming vegetable juices. Stick to normal serving sizes and limit intake to no more than one small glass per day to maximize potential benefits and avoid potential downsides.
Bottom Line
Current evidence suggests that it’s extremely difficult to eat too many whole vegetables. They are very high in nutrients and low in calories and fill you up before they fill you out. Eating a variety of vegetables has been linked to reduced risk of disease and increased longevity. Therefore, there is no established upper limit for how many vegetables you can eat per day. Most experts recommend a minimum of 3 to 5 servings or 400–500 grams per day for the average person — and well above that for optimum health. While juicing can be healthy in moderation, drinking vegetable juice instead of eating whole vegetables may increase your calorie intake and blood sugar levels and decrease vegetable consumption. Stick to no more than one small glass (4–8 ounces or 120–240 ml) of low-sugar vegetable juice per day to maximize potential benefits. Increasing your vegetable intake is always a great idea for better health, however you choose to consume them. Just focus on getting a variety of colors and types. Your body will thank you.
Frequently Asked Questions
Can you eat too many vegetables?
It’s very difficult to truly overdose on vegetables since they’re low in calories yet high volume foods. Unless juicing large quantities, it’s nearly impossible to eat enough vegetables to cause harm. Focus on getting a variety of colors and aim for at least 400–500 grams per day.
What happens if you eat too many vegetables?
Eating very large amounts of raw vegetables or greens could potentially cause digestive upset due to high fiber content. Juicing large quantities may provide excessive antioxidants, vitamins or minerals. However, there’s no established upper limit and no evidence of harm from simply eating extra vegetables with meals.
Can vegetables be bad for you?
Vegetables are very healthy and nutritious overall. However, there are a few things to consider. Some vegetables like spinach and carrots contain more pesticide residue. Cruciferous vegetables could potentially cause thyroid problems if over-consumed. And juicing removes beneficial fiber. But these concerns apply mainly to isolated components, not whole foods.
What vegetable should you never eat too much of?
Spinach, beet greens, and swiss chard contain oxalates that could cause kidney stones when consumed in extremely large quantities. Cruciferous vegetables might also impair thyroid function if consumed in excess. However, these vegetables are very healthy overall and don’t need to be limited in normal amounts.
Can you eat unlimited vegetables and lose weight?
It’s unlikely that eating unlimited quantities of vegetables alone would lead to significant weight loss since they’re low in calories. However, adding extra servings of vegetables to your diet helps reduce calorie intake from other foods and can promote weight loss as part of a healthy lifestyle.
The Bottom Line
Consuming a variety of vegetables is strongly linked to better health and lower risk of chronic diseases. Most studies suggest that the more vegetables you eat, the greater the benefits. While juicing large amounts could potentially cause issues, it’s difficult to overconsume vegetables as part of a whole food, balanced diet. Focus on getting at least 400–500 grams per day for optimal health.
