Let's make something clear: Not all vegans have a holier-than-thou attitude when it comes to their diets, and not all of them try to convert meat-eaters to their vegan ways. But for the ones who do, here's something they can chew on: Research shows that vegan diets are not good for children.

Let's break that down. What does "not good" mean, really?

Vegan diets are not always considered the best for kids (under 10) for these reasons.

1. Lack of vitamins and nutrients.

It's not completely impossible to ensure that growing children get enough nutrients on a vegan diet, but it isn't easy. "Nu­tritional balance is very difficult to achieve if dairy products and eggs are com­pletely eliminated," reports HealthyChildren.org. "Vegetarians sometimes consume insufficient amounts of calcium and vitamin D if they remove milk products from their diet."

Growing children also need sufficient quantities of vita­mins B12 and zinc, among others. "Plant foods have no vitamin B12 unless they are fortified," according to the University of Maryland Medical Center. This means that many vegans typically get their fix from a supplement, which works fine for adults, but is harder for kids.

And what's the problem with kids not getting enough vitamins and nutrients? Their growth is stunted. A study showed that children raised on a vegetarian diet wound up "slightly" shorter than their peers who were not raised on such a diet. They are also more likely to develop anemia.

2. Lack of calories.

An issue with vegan food is that it's largely plant-based, which doesn't always fulfill the necessary calorie requirements for a growing child, nor is it as satiating and satisfying. Depending on an adult male's activity level, they might need as many as 2,000 calories per day. And it may surprise you to learn that a "somewhat active" boy between the ages of 4 and 8 needs almost as many, with a recommendation of 1,400 calories a day, according to the Centers for Disease Control and Prevention growth chart featured on Livestrong.com. But a "very active" 4-year-old boy actually needs as many calories as an adult male (2,000), according to 2010 HHS/USDA Dietary Guidelines for Americans.

Adults who follow vegan diets get 20 percent less calories than those who eat meat, according to a 2014 study as presented by the U.S. National Library of Medicine National Institutes of Health. While this isn't a huge issue for adults, it can be for children, who need the proper amount of calories to ensure healthy development.

3. Lack of iron and protein.

Protein is an important part of a healthy diet. Let's go back to our active 4-year-old who's eating 2,000 calories per day. SF Gate reports, based on recommendations from health professionals, that 200 to 600 of those calories should be pure protein. On a non-vegan diet, that isn't a tall order, since you can find protein in a wide variety of foods, including yogurt, cheese, eggs, milk, steak, chicken breast, salmon — the list goes on.

But for vegans, it's a much shorter list. There are navy beans, lentils, peanut butter, mixed nuts, edamame, tofu, and protein powders. There are other sources, yes, but they're not as varied, and as such, a much tougher sell for kids, especially because it's recommended that protein should come from "more than one source," according to Healthy Children. Their food palates aren't sophisticated enough to appreciate the bitterness of certain greens or the muted tastes of certain plants.

4. Leads to potential binging on non-vegan foods.

An adult on a vegan diet can apply reason to their choices. They can understand why they eliminate certain foods from their diets. But children do not have this reasoning. If they are told that something is forbidden, they want it even more — and they'll take it.

A study published in 2007 called "Do not eat the red food!" tested children on their willpower to avoid prohibited food. Researchers presented 5 and 6-year-olds with two separate bowls of yellow and red snacks, telling the children that they could only eat the yellow foods — no red foods allowed. Then, when they lifted their ban on red foods, and the kids binged on them. Compare this to a second, different group of young children, who, when presented with the same colored food options, were not given any restrictions. These kids did not binge on red foods.

Ultimately, how you choose to feed yourself or your children is no one's business but your own.

If you want to go vegan, go vegan. But consider very carefully if that decision is a wise one for your kids. If your kid goes Lisa Simpson on you and decides for herself that she wants to be a vegetarian or vegan, help them out. But you shouldn't force a vegan diet — or any diet — on your children, unless a doctor advises you to do so.

And anyway, the benefits of vegan diets may actually be exaggerated.

[h/t Slate]