About 16 million people—roughly 5% of the U.S. population—describe their diet plan as "vegetarian," and this number has been gradually increasing in recent years. In general, this term is shorthand for a diet where most of the calories come from plant food. However, the vast majority of vegetarians consume some animal foods in their meal plan, and for this reason do not refer to themselves as "strict vegetarians" (or "vegans") who carefully avoid all animal foods.

Vegetarian Types

Below is a list of popular terms used to describe various types of vegetarian diets.

• Vegan: diet approach where only plant foods are consumed.
• Lacto-ovo vegetarian: plant food-focused diet, but including dairy and eggs.
• Pesco-vegetarian: plant food-focused diet, but including seafood. You will also see "pescatarian" and "pesca-vegetarian" used to describe this diet type.
• Semi-vegetarian: often used in research studies to describe diets that include meat and poultry more than once per month but less than once per week.
• Non-vegetarian: in research studies, often defined as diets where meat and poultry are consumed at least one per week, and typically more often.

Health Benefits Research

Research on vegetarian diets is extensive, involving more than 100,000 study participants over time. Vegetarian diets have repeatedly been shown to lower the risk of chronic diseases, including: atherosclerosis, cancers (select types), coronary artery disease, hypertension (high blood pressure), insulin resistance, metabolic syndrome, stroke, and type 2 diabetes.

Health Risks Research

The majority of studies on vegetarian diets show increased risk for low intake of vitamin B12. Some studies on vegetarian diets have shown increased risk of protein deficiency, iron deficiency, decreased muscle creatinine, and elevated blood levels of homocysteine. From our perspective at WHFoods, a high-quality and balanced vegetarian diet can typically minimize these risks, with the possible exception of vitamin B12. For more on this B12 issue, please see our specific Q & A, "Is vitamin B12 really a problem in a vegetarian diet?"

Popular Q&As About Vegetarian Diets

At WHFoods, we are often asked specific questions about vegetarian diets. You can click on any of the 12 specific Q & A topics below for practical information on each topic.

• Are vegetarian diets really more healthful?
• What do you think about a mostly vegetarian-plus-seafood meal plan?
• What do you think about a mostly vegetarian-plus-dairy/eggs meal plan?
• How does seafood compare with dairy/eggs as a "protein booster" on a vegetarian diet?
• What nutrients are most likely to be deficient in a vegetarian diet?
• How much of a problem is protein in a vegetarian diet?
• How much of a problem is iron in a vegetarian diet?
• Is vitamin B12 really a problem in a vegetarian diet?
• Can a vegetarian diet help me lose weight?
• Does WHFoods directly advocate a vegetarian meal plan?
• What if I eat vegetarian most of the time, but enjoy meat and poultry on occasion?
• If I am mostly eating plant foods, do I still need to be concerned about food quality?
• I've heard a lot about eating a "colorful diet." Should I pick fruits and vegetables based on color to help me get more benefits from these foods?
• How do our vegetable recommendations at WHFoods compare with common public health recommendations?

References

To see the research articles we reviewed in the writing of these articles, see here.

Wheat, Grains, and Gluten

We receive many questions about gluten-free foods, grain-free diets, and the "wheat belly diet" and whether or not there are legitimate and distinct health issues related to consumption of grains versus wheat versus gluten.

It is impossible for anyone to question the growing popularity of gluten-free foods in the U.S. marketplace during the period of time between 2010 and 2015. In fact, statistics from 2014 show that over 8 billion dollars' worth of gluten-free foods were sold in the U.S. supermarkets! Along with this gluten-free trend has come a wealth of debate about wheat as well as an greater popular interest in grain-free eating, wheat-free eating, and the "wheat belly diet." We have taken a close look at health research studies in this area, and we have created a short list of grain-related questions to provide you with quick access to practical information in this area. Just click on the questions below for up-to-date findings and WHFoods recommendations about these often misunderstood grain-related topics.

• What is gluten?
• Is gluten-free the same as wheat-free?
• How is wheat related to other grains?
• Is gluten sensitivity the same thing as wheat allergy?
• Can I still have an unwanted reaction to wheat or grains, even if I always choose whole grains?
• Do you consider grains to be a priority food group for healthy eating?
• Adapting a Meal Plan for Little or No Grains
• References for Articles on Wheat, Grains, and Gluten