One of the wonderful things about being human is the fact that we can eat — and thrive — on an incredible variety of diets. The breadth of our consumption choices has allowed us to live and eat locally everywhere on Earth, from the hot and humid equatorial regions to the ice-packed and agriculture-unfriendly northern Canada. People can survive on diets that are made up primarily of whale meat and blubber, fruits and nuts, dairy and grains, or olives, seafood and herbs. People can be vegetarians, and there are even various types of vegetarians.

There is no one "right" way to eat, though there are ways to eat that are lower-impact, that have a lower carbon footprint, choices that lead to less animal suffering, or diets that don't involve farming at all. One thing that pretty much every health expert I have read or spoken to agrees on for all people is that processed foods — all those manufactured foods found in the middle of the grocery store, like most cereals, chips, snack foods, pre-made meals, and sweetened drinks — should be eaten sparingly or not at all. They are full of preservatives, stabilizers, highly processed grains, artificial colors and a lot of non-nutritive ingredients that are at best useless to the body, leading to weight gain, and at worst downright harmful.

Because the state of our food systems, while more abundant (for those of us lucky enough to live in the West) than ever before, is also less healthy, many people swear by one type of eating, or follow a specific diet that they will insist is right for everyone. The truth is that nobody knows what's best for you except you. Not your mother, or your best friend, or your partner or your coworker. The best course of action is to educate yourself on the various types of diets, and then try them out for yourself, and see what works for your lifestyle, your budget and most of all, what feels best for your own body. Listening to your body is the key to long-term health.

The only thing we know for sure is that processed foods don't have much place in a healthy diet, and that a heavily meat-based diet is a strain to the planet's resources (and, in large, long-term studies, the closer your diet to vegetarian, the longer you will likely live). (Are processed meats pretty much the worst thing you can eat? Yes: they are linked strongly with a risk of early death.) So growing numbers of people are looking at whole food vegetarian or low-meat diets: Here's how they break down.

Vegetarian: Most people who call themselves vegetarian don't eat any meat, fish or seafood. Because this is the widest category of non-meat consumption diets, it is also the most varied and flexible. Some vegetarians eat eggs, some don't; some eat milk products and some don't. A person who eats milk (lacto) and eggs (ovo) is a lacto-ovo vegetarian (you might see this on airplane meal choices or in hospital cafeterias). If you know someone who simply describes their diet as 'vegetarian' go ahead and ask them if they eat milk or eggs, because this general description isn't as specific as some of the below. For example, I've been a vegetarian for 20 years now, and I eat eggs (enthusiastically), and cheese a couple times a week, but don't drink milk or consume any other dairy products. Plenty of vegetarians just don't eat meat, but they eat everything else.

Vegan: A vegan eats no animal products whatsoever (no meat, seafood or fish) including dairy, eggs and honey. They don't wear leather, silk, fur, or reptile skins, or any clothing that has material made from animals. Gelatin, certain food additives and ingredients are also on the don't-eat list.

Beegan: A newish term that applies to people who are vegan but do eat honey and foods with honey in them.

Pescetarian: This diet excludes meat, but includes seafood and fish, or just fish, depending on the person. Dairy, milk, honey and other animal products are generally included in this type of eating plan.

Flexitarians or part-time vegetarian: These diets include meat, but usually in a fairly limited fashion. The flexitarians I know tend to eat meat once or twice a week, or only when they eat at a restaurant, or only if the meat comes from a reliable source, but the vast majority of their meals are vegetarian. Flexitarians are generally very conscious of where their meat comes from and they minimize its importance in day-to-day consumption.

Vegan before 6 (VB6): This is the eating plan that Mark Bittman (of the New York Times) generally follows, and it is, essentially, a flexitarian diet. Only vegan, whole foods for breakfast and lunch, and then whatever you like for dinner.

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Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.

Vegetarian types: Understanding plant-based diets
Not all non-meat diets are the same: Here's a breakdown of how most people in these groups eats.