A “vegan diet” can often be confused with a “plant-based diet.” Dartmouth Cancer Center clinical dietician Dianne Kelecy, MS, RD, LD, unpeels both diets to explain what they really mean.
Vegan and plant-based are not the same.
A vegan diet is a very strict regimen. Simply put, this diet eliminates all animal products: meat, poultry, seafood and dairy. Believe it or not, even honey is not allowed on a strict vegan diet.
“Plant-based” sounds so much more user-friendly—but there is a difference. The American Institute for Cancer Research (AICR) defines a plant-based diet as “a diet built around a plate filled with mostly vegetables, fruits, whole grains and beans.” Plant-based would mean your plate is two-thirds plant foods and one-third or less animal products. And it would eliminate all processed foods and added sugar.
The AICR provides a wonderful visual called the New American Plate. The portion of meat is very small—I would estimate that’s probably 2 ounces of meat, which would contain about 15 grams of protein. The plate has good variety, with two different kinds of vegetables, and a very reasonable portion of brown rice. “Plant-based” would look like that.
Two proponents of a vegan diet
Now, why might someone consider a strict vegan diet? A lot of information out there claims that it will reduce the risk of cancer and other diseases. People also have concerns about animal welfare, and this is a very understandable and legitimate concern, as are concerns about the environment. There are also some religions that discourage consumption of animal products.
About ten years ago, Drs. Caldwell Esselstyn and Colin Campbell put out a powerful and convincing documentary called "Forks Over Knives," which gives a great overview of what the vegan diet is and how to follow it. They have many stories about how people transform their lives by switching from a standard American diet to an all-vegan one. When I worked in our cardiac rehabilitation program, we would show this documentary when we introduced the vegan diet to people as an option.
Dr. Michael Greger also has very exciting information on eating an all-plant diet. I loved reading his book, How Not To Die. It goes through every disease process with research studies that back up what he is saying. It's an interesting read for anybody who wants to explore this type of eating.
Words of caution
A vegan diet is not the right fit for everyone, but it's a choice. And while that choice is a good one for some, there are things you should be aware of:
First, eliminating all animal products puts you at a higher risk of protein and calcium deficiency. We all should aim to get at least 60 grams of protein per day. If you're a very active person or if your body is under stress from disease or injury, you'll need a lot more protein than 60 grams. Sometimes one gram per pound of body weight is a good target to go by in those cases.
Plants are not complete sources of protein since they don’t contain all the essential amino acids, so you have to put more thought into your daily food intake. Include lots of variety with different kinds of veggies, and lots of legumes, beans and peas—that whole category of food is loaded with protein, antioxidants and fiber. Quinoa is a nice source, and all the nuts and seeds are fantastic. Soy actually is the one exception in that it is a complete source of protein. Tofu and soy milk are good options. You might also want to consider supplementing with a plant-based organic protein drink to reach your target levels.
Second, it’s going to be harder to get omega-3 fatty acids, zinc, and vitamins D and B12 on a vegan diet. Taking supplements can resolve these deficiencies, but you need to be really aware of what you're doing.
Finally and very importantly, I want to point out that a higher risk of depression, hair loss, anemia, muscle wasting, and weak bones can occur if you're not really well educated and smart about how you're following a vegan diet.
If you are interested in starting a vegan diet, I highly recommend you work with a registered dietitian who can set you up for success and make sure your body is getting all the nutrients it needs to stay healthy and strong.
To hear Dianne's full presentation on vegan, plant-based, ketogenic, Mediterranean, and several other popular diets and diet trends, please visit the Dartmouth Health video page.