NutritionView Slideshow

Too Much of a Good Thing

When you hear about the nutritional benefits of so-called "superfoods," it can be tempting to load up your diet with these trendy ingredients. But there is no standard or definition of what constitutes a superfood, and most foods that come with health benefits also come with caveats. After all, it can be damaging to eat too much of anything — even kale. Here are some commonly touted superfoods and what can happen if you go overboard eating them.

Almonds2 / 26


Possible health benefits: Improved brain function, smoother skin
But: Some of the same qualities that make nuts wonderful in moderation, offering plenty of plant-based protein and fat, make them a problem when eaten in larger quantities. Perhaps the biggest problem with almonds is what they do to the environment. It takes 1.1 gallons of water to grow a single almond. California is the only state that produces the nuts and already has a drought problem, so your handful of almonds is only adding to the crisis.

Green Tea3 / 26

Green Tea

Possible health benefits: Improved brain function, diet aid, free radical elimination
But: Although it’s packed with antioxidants, and a go-to for many health-conscious people, anyone sensitive to caffeine knows that green tea can be a one-way street to jitters, upset stomach, and headaches, especially when consuming more than one cup a day.

Sweet Potato4 / 26

Sweet Potatoes

Possible health benefit: High in fiber, vitamins, and minerals
But: While lower on the glycemic scale than white potatoes, sweet potatoes are still a high-sugar food and can lead to blood-sugar spikes. Particularly when roasted, the sugars caramelize and become even more prone to spiking and crashing blood sugar. And if you have a tendency toward kidney stones, stay away — the high amount of dietary oxalate in sweet potatoes is likely to lead to more obstructions.

Steamed Broccoli5 / 26
Oliver Hoffmann/shutterstock


Possible health benefits: Anti-inflammatory, lower cholesterol, estrogen regulation
But: To the delight of children everywhere, there actually may be such thing as too much broccoli. This powerful vegetable contains chemicals that help regulate excess estrogen in the body, but too much of it could disrupt the natural balance of hormones, leading to unstable moods and bodily functions. For those who take blood thinners, the vegetable’s high vitamin K content can render the drugs ineffective. Those suffering from hypothyroidism should also stay away from broccoli completely, as it interferes with how the thyroid produces iodine.

Cherries6 / 26


Possible health benefits: Sleep aid, anti-inflammatory
But: Sweet and tart, cherries can be addictive when they are ripe and in season. It’s easy to overindulge, which can cause serious stomach problems. Along with severe pain and cramping, eating too many fiber-rich cherries can cause diarrhea and dehydration. And whatever you do, don’t eat the pits. While a whole one won’t hurt you, crunch into just one or two pits and you can die from their naturally occurring cyanide.

Bell Peppers7 / 26

Bell Peppers

Possible health benefits: Vitamin C, reduced risk of cancer
But: Like other foods in the nightshade family, including tomatoes, potatoes, and eggplant, bell peppers can cause inflammation in the intestines for some. Peppers also contain the alkaloid solanine, which can disrupt nerve function and lead to twitching and convulsions. Because bell peppers also pose a problem for joint health, they’re not recommended for people who have rheumatoid arthritis or osteoarthritis.

Chili Peppers8 / 26
Watermelon9 / 26


Possible health benefits: Diet aid, vitamin C
But: With no fat and a high concentration of electrolytes, watermelon seems like a dieter’s best friend, but there is a downside: Delicious, sweet watermelon has a high glycemic index without much fat or protein to balance it out, which could lead to blood-sugar spikes, which can be dangerous for diabetics. Those who try to stick to a low-glycemic diet should limit themselves to small portions after a meal or combine watermelon with a snack rich in protein and fat.

Beets10 / 26
Viktory Panchenko/shutterstock


Possible health benefits: Stronger immune system, reduced risk of cancer
But: Along with a lot of sugar, which could be problematic for people with blood-sugar issues, beets contain an element that can cause constipation. If you find yourself stopped up after going hard on the beets, ease up and add plenty of fiber — like the greens that come with the root. Beets can also cause low calcium levels and worsen kidney disease.

Cabbage11 / 26


Possible health benefits: Diet aid, gastrointestinal cleansing, reduced risk of cancer
But: Cabbage, like broccoli, is a member of the cruciferous vegetable family and can be a hormone disruptor, especially when consumed raw. Cabbage salad and soup are often used as diet foods to make up a large percentage of the day’s intake, which can lead to imbalances in mood, digestion, and endocrine function.

Eggs12 / 26


Health benefits: Energy stabilizer, nerve cell protection
But: Over the years there have been a roughly equal number of studies showing eggs as good or bad for cholesterol levels and cardiovascular health, although a recent one is a jaw-dropper. It found that for each half-egg eaten per day — totaling about three to four eggs per week — the risk of early death increased by 8%. While many people still feel eggs are a healthy part of a balanced diet, too many eggs can raise all levels of cholesterol, including the "bad" LDL.

Black Beans13 / 26

Black Beans

Possible health benefit: Gastrointestinal cleansing
But: Black beans are high in carbohydrates, which can work against anyone trying to maintain a low-carb diet with plant-based protein. Black beans can also be difficult to digest, leaving many with painful gas and bloating for up to 24 hours after eating. For people with kidney problems or who are on dialysis, black beans are not ideal due to their high phosphorous content.

Quick-Cooking Oats14 / 26
Brussels Sprouts15 / 26
Brent Hofacker/shutterstock
Turmeric16 / 26


Possible health benefits: Improved brain function, lower risk of cancer, anti-inflammatory
But: A little turmeric goes a long way. When overused it can cause digestive issues, particularly diarrhea, which leads to dehydration and an inability to absorb other essential nutrients from food passing through the gastrointestinal tract. A maximum of one-half teaspoon a day of dried turmeric is a good place to start.

Garlic17 / 26


Possible health benefits: Lower blood pressure, cold and flu protection
But: With so many lauded qualities, it’s hard to imagine anything wrong with garlic, but many people have found they are garlic sensitive or downright intolerant. Garlic, especially when raw, can cause unpleasant bloating and irritation in the intestines, along with intense stomach pain. If you’re taking it but suspect a sensitivity, try eliminating it for two weeks and see how you feel.

Carrots18 / 26


Possible health benefits: Eye health, reduced cancer risk, stable blood pressure
But: If you eat too many carrots, your skin actually may turn a yellowish hue, thanks to the large amounts of beta carotene in the sweet root vegetable. However, relying too heavily on carrots as a vegetable of choice is more likely to result in a diet too high in sugar. This is especially true when juicing carrots, which removes all the fiber that helps balance the sugar.

Bananas19 / 26
Fava Beans20 / 26

Fava Beans

Possible health benefits: Reduced risk of heart disease, osteoporosis, and birth defects
But: The larger the legume, the harder a time the body has digesting it. These large and meaty beans can be taxing on the digestive system, requiring a lot of energy and producing a lot of uncomfortable gas in the process. Think of them as a small-portion side dish, rather than the main event.

Chocolate21 / 26
Avocado22 / 26


Possible health benefits: Heart health, skin health, and mood stabilizing
But: Although avocados are rich in heart-healthy monounsaturated fats, they’re still high in fats — so if you’re eating more than a sliver a day and can’t lose weight, consider cutting back. For people with IBS, avocadoes contain polyols, which are not well-absorbed in the small intestine and can create an uptick of symptoms ranging from abdominal pain to nausea and diarrhea.

bowl of kale23 / 26
bowl of kale by Stacy Spensley (CC BY)


Possible health benefits: Immune function, bowel health
But: If you’ve been gobbling down kale salad after kale salad for your health, you may want to slow down. Consuming too much, paired with an iodine deficiency, can result in lowered thyroid function. And according to the Environmental Working Group, some non-organic kale has been found to be contaminated with a potentially carcinogenic pesticide that is banned in the European Union. The other issue: Even chefs agree the stuff is totally overrated.

Protein Powder24 / 26
Jean Pierre Pinochet/istockphoto

Protein Powder

Possible health benefits: Muscle repair, improved immune function
But: Lots of people love to toss a scoop (or three) in their smoothies right before or after a workout, but don’t go too crazy with the stuff. Too much protein powder can cause dehydration, kidney damage, and bone damage. There’s also some doubt as to whether or not protein powder is necessary anyway — most people get enough of it in their diets, and there’s no proof that the powder actually helps build or repair muscle.

Coconut Oil and Fresh Coconuts25 / 26
Spinach26 / 26


Possible health benefits: Anti-carcinogenic properties, good source of iron
But: Spinach containes oxalates and purines, increasing your risk of gout and kidney stones, but if you’re still going to eat it, go organic. The regular stuff has more than 48 pesticide residues, according to the U.S. Department of Agriculture’s Pesticide Data Program, one of the highest amounts tested. That means this "health food" can put you at an increased risk of cancer as well as hormone disruption.