Low meat vs. no meat: Which diet is best for cancer prevention?

There’s no way around the fact that eating too much red meat and processed meat can increase your risk of cancer.

Even lean proteins like chicken and fish should be kept to one-third of your plate or less. And ideally, for cancer prevention, you should incorporate plant protein.

So is it easier and healthier to just quit meat altogether? We took a look at three diets that cut out or seriously limit meat. MD Anderson dietitian Karla Crawford has the pros and cons of being vegan, vegetarian and flexitarian.

Vegans eat no animal products at all. Meat, fish, dairy and eggs are all off the menu. For the very strict, honey is a no as well, because it comes from bees.

Pros

New research suggests that vegans have the most diverse microbiome. The microbiome is the collection of bacteria in your gut that breaks down foods and helps you absorb vitamins and minerals, including essential phytochemicals and antioxidants.

If your microbiome is healthy, you take in more nutrients. A healthy microbiome also protects you from substances like viruses or disease causing bacteria like E-coli or listeria.

“Plant foods provide your body with indigestible fiber, and the good bacteria in your intestines feed off this fiber,” says Crawford. “With a vegan diet, a person has more opportunities to be exposed to those fibers in addition to phytonutrients.”

Having a healthy microbiome may lower your risk of obesity or weight gain, and in turn, lower your risk for cancer.

Cons

Vegan diets are highly restrictive and can be hard to follow. Depending on where you live, it can be hard to find food on the run.

And your local eateries and grocery stores may not offer plant-based protein options like quinoa, soy and other meat substitutes.

If you are vegan and don’t get enough protein, it can lead to muscle wasting.

Vegans must also make sure they get enough vitamin B12, which is generally found in meat and dairy products.

Vegetarians do not eat meat, but they do eat other animal products like dairy and eggs.

Pros

If you eat a healthy vegetarian diet, and include dairy products, you will still get a lot of nutrients. This is key if you want to reduce your risk of disease.

It’s also easy to get enough protein and vitamin B12 if you eat dairy and eggs. This can make being vegetarian a little simpler than being vegan.

And most restaurants have vegetarian options, so that will make it easier to stick to your diet when you are out and about. Plus, your vegetarian diet won’t be wrecked if you are tempted by an occasional tasty creamy dessert.

Cons

A vegetarian diet can  provide enough protein and vitamins if you make the right choices. But just as in any diet, you must make sure you don’t slip into relying on unhealthy foods to feel full.

“This risk is you end up on a bread and cheese diet,” says Crawford. “To make sure you are not hungry, you will need to incorporate plant-based sources of protein like beans and legumes, whole grains such as quinoa, brown or black rice, and whole grain pasta.”

A flexitarian is someone who focuses on eating fruits, vegetables and whole grains, but does incorporate some meat and dairy. They might eat meat two or three days a week and on others days get some protein from dairy. But flexitarians get a large amount of their protein from plants.

It is essentially the same as a plant-based diet.

Pros

Flexitarian diets can be practical for people who want to eat healthy and reduce their cancer risk. The focus on plants means they get a lot of phytochemicals and antioxidants. The large amount of fiber also promotes good gut health.

Flexitarian diets also avoid some of the pitfalls of veganism and vegetarianism. It’s easy to get enough protein and vitamin B12 even with a small amount of meat.

Cons

A flexitarian diet can be too flexible. If you don’t watch portion sizes carefully, a little meat here and there can soon put you back with meat and animal products at every meal.

It’s essential to commit to changing the focus to vegetables, fruits, whole grains and plant proteins. Aim for only 5-6 ounces of animal protein a day. That would include dairy products like milk, yogurt, cheese and eggs.

Healthy meat choices include lean proteins like chicken or fish. Too much red meat – more than 18 ounces of cooked red meat per week - will increase your cancer risk. Avoid processed meat.

Plants are the key to any healthy diet

No matter which of these diets you choose, switching your focus to plants is the most important change to make.

The fiber, phytochemicals and antioxidants you get from plants work to help keep your body disease-free.

 “The basic idea is always going to stay the same,” says Crawford. “Any healthy diet must be based on lean proteins, fruits, vegetables and healthy grains. That’s not going to change.”