Omnivore, Vegan and Vegetarian Diets Explained

Have you thought about changing your diet to improve your health? Many people have. Research shows that about 10 percent of Americans today consider themselves vegetarians, with about half of them having followed that diet for 10 years or more. About 0.5 percent of those ― an estimated 1 million ― are vegans.

When asked why they went on these diets, about half answered: “to improve overall health” while others cited reasons like environmental concerns and animal welfare.

However, what is a vegetarian or vegan diet, and how do they differ from the standard Western diet? Most importantly, could it help you to become healthier?

What Is an Omnivore Diet?

If you’re an omnivore, you eat food that comes from both plants and animals. The word comes from the Latin words “omni,” which means “all” or “everything,” and “vorare,” which means “to devour.”

The omnivore diet is the most common diet among humans today and offers the widest variety of food choices. On this diet, you can enjoy meat, dairy, fruit, vegetables or any other food you like. It is for this reason that this diet can be very healthy and balanced or very unhealthy and unbalanced — it’s all in how you approach it.

Health Benefits

The good thing about this diet is that you have a wide variety of foods available to enjoy, which increases your odds of getting all the nutrients you need for good health. If you’re low on a certain nutrient, you have many food options for upping your intake.

The presence of meat and other animal products in this diet also provide needed vitamin B, iron, zinc and magnesium as well as a complete form of protein that is absorbed easily by the body. Meat also contains creatine and carnosine, which benefit both the bones and the brain.

Health Concerns

The health concerns with the omnivore diet include:

  • Too much unhealthy fat: Fatty red meat contains saturated fat, which if you’re not careful, can lead to overweight and obesity and related issues like high cholesterol, type 2 diabetes and cardiovascular problems.
  • Too much sodium: Processed meats, in particular, are high in sodium, which has been linked to health problems like high blood pressure and cardiovascular disease.
  • Too much fast food: Fast food provides easily available meat, but it’s often fatty, greasy and salty and tends to contribute to the health problems possible with this diet, including chronic inflammation.
  • Digestive issues: If omnivores focus too much on meat and not enough on plant-based foods, which typically provide more fiber, they can suffer from digestive problems like constipation, gas and bloating.

How to Eat Healthy as an Omnivore

To make your omnivore diet as healthy as you can, follow these tips:

  • Choose your meat carefully: Look for grass-fed beef and lean cuts of pork, chicken and turkey. Consider wild meat as well like elk, deer and buffalo as these tend to be leaner. Also, look for livestock that was raised without the use of antibiotics and growth hormones.
  • Avoid unhealthy trans fats: Stay away from foods with “partially hydrogenated oils” as these have been linked with heart disease.
  • Enjoy a wide variety of food: To take full advantage of this diet, keep shaking it up. Try different sorts of meats as well as new fruits and veggies. The more colorful your plate, the more nutrients you’re getting from your food.
  • Watch your weight: This diet is the most likely of the three to lead to overweight and obesity, so limit your portion sizes and make sure you’re exercising every day.

What Is a Vegetarian Diet?

If you’re a vegetarian, you avoid eating most animal-based foods, but you may make some exceptions. In general, there are six different types of vegetarians:

  1. Semi-vegetarian: You avoid meat most of the time, but you may indulge once in a while with a little meat and/or fish.
  2. Lacto-ovo vegetarians: You avoid meat, poultry and fish, but you do enjoy dairy products and eggs.
  3. Lacto-vegetarians: You avoid meat, eggs, poultry and fish, but you enjoy dairy products.
  4. Ovo-vegetarians: You avoid meat and dairy products but allow eggs.
  5. Pescatarian: You avoid meat, dairy and eggs, but allow fish.
  6. Pollotarian: You avoid most meat, dairy and fish, but allow poultry.

The vegetarian diet is thought to be healthier than an omnivore diet, but that’s not necessarily true. It all depends on how you manage your diet. A well-managed omnivore diet can be very healthy as can a well-managed vegetarian diet, but a vegetarian does have a more limited food supply, which can result in some nutrient deficiencies if you’re not careful.

Health Benefits

One of the main benefits of a vegetarian diet is that it can help you lose weight. In a study of about 38,000 people, researchers found that those who ate only fish for meat, as well as vegetarians and vegans, had a lower body mass index (BMI) than those who ate other types of meat.

Other studies have indicated that vegetarians frequently have lower cholesterol levels than meat-eaters. In a 2003 study, scientists found that participants who already had high cholesterol who went on a vegetarian diet lowered their cholesterol levels by almost 30 percent, which was only slightly less than that experienced by patients taking a cholesterol-lowering medication.

Those who follow a vegetarian diet seem to have a lower risk of cancer overall. In a 2009 study, researchers found that the overall cancer rates were lower among vegetarians than meat eaters, with one exception — vegetarians had a higher incidence of colon cancer, but researchers weren’t sure why.

Finally, a vegetarian diet may help protect your cardiovascular system and may lower your risk of type 2 diabetes. Studies have found evidence of both. Researchers believe that’s because vegetarian diets tend to be lower in saturated fats and higher in fiber.

Health Concerns

The health concerns with the vegetarian diet include:

  • Nutrient deficiencies: Because this diet is more limited than the omnivore diet, it may create nutrient deficiencies. Vegetarians have to watch carefully levels of vitamin B12, iron, protein, vitamin D, calcium (if you avoid dairy products), iodine and zinc.
  • Low protein: If you’re not eating meat, you’re likely to eat less protein overall. Protein is essential to good nutrition. The protein in plant-based foods doesn’t have the same amino acid profile as animal-based foods, so the body can’t absorb it as easily. Without enough protein, you may notice that the skin looks dull, wounds take longer to heal, you may feel weaker, digestive issues may show up, and you may suffer from brain fog.
  • Weight gain: Although many people lose weight on a vegetarian diet, weight gain is still a risk if you don’t manage your diet well. The biggest risk is eating more carbohydrates to replace the lost protein in the diet. Also, some people who go on this diet to lose weight may succeed, but then find that they rebound because they feel hungrier than usual.
  • Omega-3 fatty acids: These are important nutrients for heart health, but we get them mostly from fish and eggs. Without these foods, you may not be getting enough. Fatty acids are also critical for helping the body to break down and utilize the protein.

How to Eat Healthy as a Vegetarian

To make your vegetarian diet as healthy as you can, follow these tips:

  • Go gradual: If you haven’t tried this diet before and you want to try it, make gradual changes — don’t go off all meat all at once, for example. This can put your body into a type of shock, which increases your odds of failing on the diet. Instead, make well-thought-out shifts week by week until you get to where you want to be.
  • Choose foods to fill nutrient gaps: It’s important to include certain foods in your diet to avoid nutrient deficiencies. Good sources for each of the potentially missing nutrients are listed as follows:
    • Iron: Sea vegetables (like nori), fortified breakfast cereals, dried fruit (figs), broccoli, legumes, grains (quinoa), nuts and seeds and collard greens.
    • Vitamin B12: Meat substitutes, breakfast cereals, vegan spreads (like Marmite), yogurt and low-fat milk, cheese, eggs and nutritional yeast.
    • Protein: Hummus, rice and beans, soy, quinoa, Ezekiel bread, seitan, nut butter, eggs, beans, lentils, milk, whey and yogurt.
    • Vitamin D: 15-30 minutes of sunshine, fortified products and supplements.
    • Zinc: Seafood, beans, nuts, whole grains, fortified breakfast cereals, Tofurky, cheese, yogurt.
    • Calcium: If you avoid dairy products, consider taking a daily calcium supplement. Taking it at the same time as you take iron or zinc supplements may help the body absorb it more efficiently.
    • Iodine: Without enough iodine in the diet, your thyroid can suffer. If you avoid dairy products, eggs, and/or seafood, make sure you get some iodized salt and sea vegetables in your diet. If you’re limiting your sodium intake, try an iodine supplement.
  • Get more omega-3 fatty acids: Good sources include canola and soy oil, walnuts, ground flaxseed and soybeans. The body doesn’t process the omega-3s in these foods as efficiently as it does in animal-based foods, however, so you may want to consider an omega-3 fatty acid supplement, such as algae oil.
  • Cook in a cast-iron skillet: When you cook foods in cast iron, you get a little bit of the iron in your meal, helping to reduce the risk of this nutrient deficiency.

What Is a Vegan Diet?

If you’re a vegan, you consume only plant-based foods and eliminate all animal-based products. That means no meat, poultry, fish, eggs, dairy products or honey for some strict vegans. Vegans choose instead to focus on fruits and vegetables, grains, legumes, nuts and seeds, tofu and tempeh, plant-based oils and natural sweeteners like coconut sugar and maple syrup.

Many vegans also apply this philosophy to their lifestyles and believe in avoiding clothes, makeup, personal care products and entertainment that they feel exploits animals.

Health Benefits

What’s good about the vegetarian diet can also be applied to the vegan diet, in most cases. Because it’s lower in saturated fat, it can help you lose weight or maintain a healthy weight. In a 2005 study, for example, researchers found that a low-fat, vegan diet was associated with significant weight loss in overweight postmenopausal women, even though the women didn’t control portion sizes or calorie intake. Another study found that even when compared to a modern low-fat diet, the vegan diet was still associated with significantly more weight loss at the one- and two-year checkpoints.

The vegan diet may also help protect against cardiovascular and other diseases like cancer. In a 2014 study, researchers reported that the diet protected against cardiovascular disease, some cancers and high blood pressure.

Like the vegetarian diet, the vegan diet may help reduce the risk of type 2 diabetes. In a 2006 study, for example, researchers found that a low-fat vegan diet helped to improve both blood sugar levels and fats in the body for patients with type 2 diabetes.

Vegan diets may also have some other benefits, like helping to reduce symptoms of arthritis pain and reducing the risk of Alzheimer’s disease.

Health Concerns

The health concerns with the vegan diet are the same as those with the vegetarian diet. However, because of the restrictions, nutrient deficiencies can be even more of a concern.

How to Eat Healthy as a Vegan

To make your vegan diet as healthy as you can, follow the same tips like those listed above for vegetarians, and make sure to keep track of your nutrient and energy levels.

Bottom Line

As you can see above, each of these three diets has its pros and cons. If you’re struggling with overweight or other health issues, feel free to try a different diet if you’d like — be sure to approach it wisely and to keep track of your nutrient levels so you won’t hurt yourself.