Vegetables get a lot of good press in healthy eating circles because they’re one of the few things everyone agrees on. From strict USDA adherents to radical vegans to Paleo dieters, everyone can rally ‘round the broccoli. There’s nothing wrong with this – and it’s definitely true that most people in the modern world need to replace a lot of the processed junk on their plate with vegetables (ketchup doesn’t count!). But that doesn’t make veggies the final word on a healthy diet. As a food group, they have some drawbacks as well as benefits, and they’re healthiest when eaten as part of a balanced diet, in conjunction with nutrient-dense animal foods.
Vegetables and the Perfect Food Syndrome
Maybe it’s just part of human nature to constantly be searching for the One True Solution to all our problems. The monthly rotation of new “miracle foods” certainly takes advantage of that urge (acai berries? Green tea? Chia seeds? Resveratrol?). But even if you don’t succumb to each new fad, it’s definitely possible to get too fixated on one specific food or food group as the ultimate in nutrition: the Perfect Food Syndrome.
Vegetables are one example of this. Run a Google image search for “healthy food” and you’ll turn up picture after picture of lovingly arranged carrots and broccoli. The individual emotional response to this is huge - digging into a huge bowl of spinach just feels virtuous. It’s very easy to get stuck in the mindset that all vegetables are healthy for all people at all times, that there’s no such thing as too many veggies. Some people take it to an incredible extreme by going on vegetable juice cleanses, drinking only vegetable juice for days at a time to “detox” or lose weight faster.
Paleo isn’t a crazy juicing cleanse, but even on Paleo it’s possible to get caught up in eating too many vegetables, or eating them for the wrong reasons. Even after reading all about how fat won’t make them fat, some people are still nervous about all the calories, saturated fat, and cholesterol in red meat. They don’t want to go back to grains, but they’re not quite willing to take the leap of faith and enjoy their steak, so they substitute endless piles of salad. Other people are afraid of the carnal pleasure of eating meat, and eating vegetables gives them that ascetic pleasure of doing their nutritional duty. They “fill up” with vegetables because they’re afraid of their own appetites.
In both of these cases, vegetables are “safe” foods because they’re Paleo-approved but don’t stray away from conventional nutritional advice either. But eating a diet with too many vegetables relative to the amount of meat and eggs deprives your body of the energy and nutrients it needs to thrive. Paleo isn’t just about getting rid of grains; it’s about substituting animal products (not vegetables!) as a staple source of calories.
This article takes on some of the dangers of eating too many vegetables relative to meat and animal products. It can seem pretty discouraging to learn about the downsides of all those leafy greens, but bear in mind the big picture: it’s not that vegetables are unhealthy; it’s that all foods have their benefits and drawbacks. Nothing is beneficial if you eat it to excess, or if it crowds out other foods that you also need. Vegetables don’t provide all the micronutrients a human body needs, and the benefits aren’t limitless: there comes a point where eating more isn’t better. As part of a balanced diet, they’re indispensable. As a “miracle cure” on their own, or as an answer to emotional needs, they’re ineffective at best.
Vegetables and Micronutrients
Vegetables’ main claim to fame is their content of vitamins and minerals, considered relative to their caloric content. But how micronutrient-rich are they, really?
Vegetables are nutritious, but there isn’t some magical dichotomy in the human diet where animal foods provide calories and vegetable foods provide nutrients. There are plenty of vitamins and minerals in animal products that you can’t get from vegetables:
- Vitamin B12, which is critical for mood and mental health, is found only in animal products.
- Iron is available in plant foods, but the non-heme iron in vegetables like spinach and broccoli isn’t as easily absorbed as the heme iron found in meat, so animal sources of iron are better.
- Vitamin A is the same as iron: there’s a form of pre-Vitamin A in plants called beta-carotene, but this has to be converted in your body, and the conversion process isn’t very nutritious. It’s much more effective to get animal forms of Vitamin A (called preformed Vitamin A, or retinol).
- Zinc is found predominantly in animal foods, especially oysters.
- Vitamin D is rare in all foods, but the only foods that contain even a little are animal products like eggs and fish.
Also, some of the fat-soluble vitamins in the veggies themselves aren’t available to you unless you also eat the vegetables accompanied by some fat. For example, you can’t really absorb Vitamins A and K without fat, no matter how much of them you eat in carrots or cauliflower. If your dinner is steak and asparagus, the steak is at least as important to your health!
Another reason why vegetables aren’t as nutrient-dense as you might think has nothing to do with the plants themselves. It’s simply the way we grow them. Think of the differences between a traditional family farm (the way we grew our produce for thousands of years) and a huge industrial agriculture operation. The family farm would have had animals in addition to vegetables, and would have grown many different kinds of plants – after all, if a farmer just grew kale, his family would starve.
This system was ideal because it constantly replenished the soil with the nutrients that the plants needed to grow. Vegetables are high in vitamins and minerals because they take them from the ground, so planting a field of vegetables is actually very hard on the soil. The most nutritious veggies – especially the brassica family, which includes broccoli and kale – take the most out of the land (by contrast, legumes actually add nitrogen to the soil).
Home gardeners know this, and rotate the plants in their gardens accordingly to give the soil a chance to rest. A small family farmer who raised animals in addition to plants had a ready-made solution to this problem: plenty of fresh manure. But modern agriculture separates animals and plants, and crams the animals into factory farms where their waste products get dumped out into rivers and streams to pollute the local ecosystem. Meanwhile, the vegetables in the fields are deprived of all these vital nutrients. Modern farmers do use fertilizers, but the fertilizers only contain three minerals: nitrogen, potassium, and phosphorous (abbreviated NPK). Meanwhile, the soil is becoming steadily more and more depleted, and the vegetables that grow in it are becoming less and less nutritious.
Not only are the vegetables lower in nutrients when they come out of the ground, but they’re also often trucked long distances in freezer trucks – this can result in significant nutrient degradation. For example, green beans lost 77% of their Vitamin C after just 7 days in storage. So the amounts listed on the Nutrition Facts panel might not actually be what you get from your salad, and there’s no real way to tell.
The upshot is that vegetables contain a lot of good stuff, but they just don’t provide everything a healthy human needs. Instead of thinking that vegetables provide nutrients while animal foods provide calories, think of the two as working together. A diet can be unhealthy if it has too few vegetables, but also if it has too many vegetables at the expense of necessary animal foods. In our diet and in our food production system, plants and animals naturally work together, and when humans try to destroy this symbiosis, we see the negative effects both on our bodies and on the planet.
Juicing and Juice Fasting
The nutritional incompleteness of vegetable foods is most obvious when you prepare them in a way that allows you to consume more vegetables than you would ever eat in solid form, and especially when you eat those super-concentrated vegetables as your only source of nutrition. In the same way that a piece of fruit and a glass of fruit juice are completely different to your body, a head of broccoli and a glass of veggie juice are also different, Juice fasting (drinking only juice for extended periods of time) really highlights the nutritional drawbacks of vegetable overload, even though the vegetables themselves are perfectly healthy when eaten as one part of a normal diet.
First of all, juice fasting provides very imbalanced nutrition, since you aren’t getting the vital nutrients only found in animal products, and you aren’t even getting all the nutrition from the veggies without any accompanying fat. As well as getting too few of some nutrients (like iron and B vitamins), it’s also possible to get too many of others; for example, some juice fasters see their skin take on an orange color from drinking too much beta-carotene in carrot juice.
Long-term juicing is also a risk for mineral imbalances. Vegetables are rich in potassium (which your body needs), but poor in sodium (which your body also needs). Fasting on vegetable juice can actually lead to a sodium-potassium imbalance, which is hard on your mood, your energy levels, and your thyroid.
Another disadvantage of vegetable juice is that it’s quite high in sugar. This seems surprising because un-juiced vegetables have almost no sugar relative to their bulk, but the juicing process presses all the fiber out, and fiber is what gives vegetables most of their size. Fiber-less vegetable juice is much higher in carbohydrate by weight, so vegetable juice has a significant sugar hit overall, especially if you use a lot of sweeter vegetables like beets or carrots.
A lot of people claim they feel amazing whey they “detox” with juice fasting, but most of these people eat a diet full of toxins the rest of the time – of course they feel better when they take away the gluten and the soybean oil! But you can get that fantastic feeling and have a diet that’s sustainable and healthy in the long term by avoiding these toxins in your foods all the time. No juice fasting required.
Again, this isn’t to say that vegetables themselves are bad for you. Fasting on vegetable juice for weeks on end is very different from eating some zucchini noodles with your meatballs. It just points out that no single food group is a perfect source of all nutrients. Vegetables are healthy food, but they shouldn’t be your only food.
Vegetables aren’t only incomplete sources of nutrients; for some people they can be downright harmful. First of all, vegetables are like grains and legumes in that they need to develop natural pesticides to survive. They can’t run away from insects, fungi, or other predators, so they rely on chemical defenses.
Many common vegetables (like zucchini, rhubarb, and bamboo shoots) contain a variety of toxins for this reason. The famous antioxidants that make vegetables so healthy are actually part of the plant’s natural defenses against predators. If you’re eating the plant, that predator is you. That isn’t to say that the antioxidants are actually dangerous – they are healthy, but they’re healthy as a hormetic stress: your body reacts to the challenge by bouncing back stronger than it was before. Hormetic stress is valuable in small amounts, but too much of it is just as dangerous as any other kind of stress.
As well as containing hormetic stressors, some vegetables cause an unpleasant reaction because of the type of carbohydrate they contain: these carbohydrates are called FODMAPs. FODMAPs vegetables are so numerous and sensitivity to them is so common that these vegetables get their own article. Essentially, FODMAPs carbohydrates aren’t completely broken down and absorbed in the intestinal system. All people have the same inability to completely digest them, but most of us aren’t sensitive to the low amounts in a normal quantity of vegetables. In FODMAPs-sensitive people, though, even a normal serving can cause bloating, digestive upset, and gut bacteria overgrowth. Common FODMAPs vegetables include onions, garlic, cabbage, and asparagus.
Nightshades are another class of vegetables that can be less than ideal. The nightshade family includes potatoes, tomatoes, bell peppers, and eggplant; these veggies contain lectins that can exacerbate autoimmune issues and trigger joint pain. Again, most people aren’t sensitive at all, but people who are sometimes see dramatic results from getting the nightshades out of their diet.
Hypothyroid symptoms are an additional reason to watch your vegetable intake. Some vegetables, especially cruciferous vegetables like broccoli and cabbage, contain a type of chemicals called goitrogens. Goitrogens aren’t dangerous at all for healthy people, but an excess of goitrogenic foods can be dangerous for people who have poor thyroid function.
Some of these substances can be destroyed or reduced by cooking – nightshade lectins and goitrogens, for example, are both decreased during the cooking process. On the other hand, fermentation actually increases the goitrogen content of a food, so skip the sauerkraut if you have hypothyroid problems.
If none of these potential gut irritants give you any problems, that’s great. Dietary restrictions that are useful for sick people aren’t necessarily warranted for healthy people, so there’s absolutely no reason to limit any class of vegetables that doesn’t upset your stomach. But the number of potential vegetable intolerances should point out that not all plant foods are automatically healthy for everyone, especially eaten in excess.
Veggies, the Environment, and the Modern Farm System
Another reason why vegetables aren’t flawless angels of nutrition is their cost to environmental and human health. Most of us in Paleo circles are aware of the problems of factory farming and the need to develop a more wholesome and sustainable food system, but we don’t usually think of vegetables as raising the same issues. Unfortunately, plant foods aren’t as ecologically friendly as the vegan crowd would have us believe. Vegetable farming can be just as polluting and also just as cruel as factory farming.
First of all, the toxic pesticides and herbicides that we spray on the fields are dangerous not only to the people who eat the vegetables, but also to the land surrounding vegetable farms. These chemicals leach into the air and water, and become environmental toxins that damage local ecosystems and human health.
Organic food isn't necessarily much better here – yes, organic farmers use more natural chemicals, but because these chemicals are less effective, they have to use more of them. A better alternative is to join a CSA or find another local source or produce – not only is this often cheaper, but you can ask the farmer directly about how the food was grown and what was or wasn’t sprayed on it. As a bonus, local food also doesn’t lose as many nutrients in transit from the field to your fork.
Another strike against the modern farm system is not really about the health of the vegetables themselves, but about the human cost of food production. Vegetarians and vegans who avoid animal products out of fears about cruelty would be horrified to learn the actual working conditions on many vegetable farms. Many farmworkers are recent immigrants (often living in the country illegally) and subject to terrible working conditions. They handle dangerous tools (sometimes without the proper safety gear and training), they’re constantly in contact with toxic pesticides at much higher levels than anything you get from eating the produce, and they’re stuck in such an exploitative cycle of poverty that they frequently can’t afford to take a day off if they get sick, for fear they’ll be fired.
Many victims of these terrible working conditions children, because a loophole in US law allows children under 16 to do agricultural labor. Farmworkers don’t receive overtime pay and are not allowed to unionize. Conditions are so bad that a group of farmworkers in Florida, the Coalition of Immokalee Workers, has launched a campaign against “modern-day slavery,” citing farmworkers’ average yearly wage as less than $12,000.
This isn’t to say that vegetable farming is inherently abusive, or that people who buy and enjoy vegetables are evil. Refusing to eat vegetables is not the answer: these foods are healthy parts of our diet, and one person’s boycott won’t do anything to stop the abuses of powerful corporations. But understanding the abuses of vegetable farming strips off the automatic halo of virtue that surrounds anything green and leafy. In Paleo circles, we spend a lot of time criticizing factory farms and the horrible conditions that animals have to endure. We should also be aware of the environmental and human cost of our vegetables, and work to make all our food as cruelty-free as possible.
The Bright Sight of Veggies
This article points out a lot of potential downsides of vegetables, but it’s important to keep it all in perspective: nobody is suggesting that you never touch green plant matter again. Vegetables are wonderful! They’re delicious and add variety to your meals, and they’re rich in several important nutrients. The real danger lies in seeing vegetables as the ultimate goal of a healthy diet, because no one food group by itself is perfect. Veggies aren’t the “holy grail;” neither is meat. Neither are eggs. Neither is liver, fermented cod liver oil, butter, water, or anything else. Searching for the “one true food” is dangerous and futile because humans are naturally omnivores.
The perception of vegetables as flawless vehicles for nutritional salvation also ignores the steep environmental and human costs of our agricultural system. Eating vegetables carries the same weight of ethical responsibility as eating meat – if we’re going to make healthy food sustainable for everyone on the planet, we have to address these problems.
Instead of exulting vegetables as the final word on nutrition, think of your diet as an archway. If you build an archway without mortar, each stone is critical to holding up the whole construction. Take out any one stone, and the whole arch will collapse. Vegetables are one, and only one, stone. They’re necessary but not sufficient – eat them and enjoy them, but don’t expect kale, or anything else, to be a miracle cure.