This article has been Fact-Checked by Kendall Kennedy MS, RD, RYT
Some people start the vegetarian diet for the animals, others think it improves their health. Does this diet actually help you lose weight?
Vegetarianism is not something new. There are multiple mentions in the history books of people who didn’t eat meat. That doesn’t necessarily mean that it’s the best diet for weight loss of course.
Guidelines of the vegetarian diet
The rules of the vegetarian diet are fairly simple. You don’t eat meat from animals but you can still eat eggs and dairy products.
So basically avoid foods like:
- Red meat
- Fish and other seafood
There are multiple other versions of the vegetarian diet, no eggs, or no dairy, or still eating fish and the list goes on. This article will focus on the vegetarian diet as described above. Things like the environmental and spiritual impact will not be discussed.
Difference between animal and plant-based protein
At first, it might sound like all protein is the same but that’s not the case.
Protein is made of smaller building blocks called amino acids. There are about 20 different amino acids that make up the protein in the human body (1).
Foods usually contain multiple amino acids in different quantities. In general animal-based protein contains larger amounts of different amino acids than plant-based protein.
There are multiple theories about what consequences the different amino acids have for your health.
Benefits of the vegetarian diet for weight loss
There are both benefits and disadvantages of going on the vegetarian diet. Depending on what diet they are on right now, a lot of people drastically increase the amount of plant-based whole foods they eat.
Less potentially unhealthy nutrients
Animal meats generally contain more saturated fat, cholesterol, and calories compared to plant-based foods.
While historically thought to be bad, the general consensus on dietary cholesterol is changing. It’s not entirely clear whether this nutrient actually causes that many negative side effects (2). If you or members of your family have a history of high cholesterol you might want to reduce dietary cholesterol intake anyway.
The role of saturated fat in dietary health context is also not completely clear. You may again want to avoid this nutrient just in case.
The calorie aspect can definitely be helpful when trying to lose weight.
This usually means that they eat more fiber, vitamins, and minerals.
Fiber has multiple benefits. First of all, it feeds your microbiome, the microbes that live in your intestines. The health of your microbiome influences your body’s health and weight. Feeding it well is usually not a bad idea.
Fiber also helps you feel less hungry without adding a lot of calories to your diet. Hunger and cravings can be a big pitfall for people trying to lose weight, so avoiding this is a big plus.
Vitamins and minerals are nutrients your body absolutely needs to survive and thrive. These are involved in basically every aspect of your health, including weight loss.
That being said, not all people who turn vegetarian eat more vegetables and not all people who are not vegetarian don’t eat vegetables. More vegetables are usually a good idea if you want to lose weight, no matter what diet you are on.
Less animal protein?
It’s very likely that vegetarians will eat less animal-based protein than other people (still a small amount from eggs and dairy).
The thing is that it’s not entirely clear whether this is a good thing for weight loss. Some people claim animal protein makes people fat others say it doesn’t matter that much.
In the absence of clear evidence or knowledge about how the mechanics around amino acids work, it’s smart to assume that you need all different nutrients.
Disadvantages of the vegetarian diet for weight loss
There are also some concerns about the vegetarian diet for weight loss. It’s important to know both the potential upsides and the potential downsides so you can make an informed decision.
Potential nutrient deficiencies
Animal-based protein is high in certain important vitamins and minerals.
The main vitamin for concern is B12. The only options for getting this vitamin are animal-based foods or supplementation. Often it is preferable to get your nutrients from whole food sources instead of supplementation.
It’s not always clear what the side effects of long term supplementation are and what nutrients you are missing out on by not eating the whole foods.
To consume the RDA (Recommended Dietary Allowance) for an adult of vitamin B12 (2.4 mcg-2.8 mcg) you would have to consume about 500 grams of fruit yogurt or 5-6 hard-boiled eggs or 75 grams of swiss cheese a day (2).
All in all, it’s certainly possible to get enough vitamin B12 if you eat enough eggs and dairy products. You just have to pay attention to it as a vegetarian.
One of the facts of a vegetarian diet is that there will be other nutrients you may lack too. Some other nutrients you might want to pay attention to are omega-3 fatty acids (mainly DHA and EPA found in fish), zinc, and iron.
All these nutrients are important for both your short-term and long-term health.
Many foods are fortified with B vitamins, vitamin D, iron, and zinc (such as non-dairy milk, tofu, cereals, etc.) to ensure that micronutrient deficiencies do not occur. Be sure to check nutrition labels or consult your healthcare provider if a supplement may be needed.
More challenging to get enough protein
A disadvantage more closely related to weight loss is protein.
Protein is an essential nutrient for humans. You literally can’t live without it. It is also helpful for building muscle which is very helpful for losing weight. Protein can also be helpful in reducing hunger.
The amount of protein in plant-based foods is often a lot lower per 100 grams than meat. The protein in plant-based foods may also be not as easy to absorb as animal-based protein (3, 4). For these reasons some vegetarians struggle to consume their daily protein intake.
You can definitely consume enough protein on a vegetarian diet, it may just be slightly more challenging.
Processed foods are technically allowed
This potential downside is also a part of a non-vegetarian diet of course.
This is just a reason why a vegetarian diet is no guarantee for weight loss succes.
Processed foods can contain a lot of calories and other unhealthy ingredients without filling you up that much. This makes it easier to eat way too many calories to lose weight.
Why do vegetarians lose weight?
Every story is different but usually people who lose weight with the vegetarian diet eat a lot more vegetables.
By increasing the amount of fiber, vitamins, and minerals you eat, losing weight becomes a lot easier.
It’s true that meat can be fairly calorie-dense but often not that much compared to a lot of processed foods that are still allowed on a vegetarian diet.
If someone would keep eating meat and also increase their vegetable intake they would most likely lose weight too.
How to lose weight healthily on the vegetarian diet
You can lose weight both with and without the vegetarian diet. It’s hard to argue that animal meat is the main thing that makes people overweight.
There are some things you need to keep in mind to lose weight healthily on the vegetarian diet.
Eggs and dairy are your friends
Eggs and dairy products are vegetarian-approved sources of animal-based protein.
That means they can help you get your daily intake of important nutrients like protein and vitamin B12.
Some people are allergic to dairy products. In that case, it’s probably better to stick to eggs.
Avoid processed foods
For both vegetarian and non-vegetarian diets one of the main causes of weight gain is eating too many processed foods.
These foods are often high in calories and unhealthy ingredients and not very filling. this makes it easier to overeat on them.
Pay attention to protein
Eating enough protein is essential for your health and very important for your weight loss.
Plant-based protein foods tend to be lower in protein per 100 grams and harder to eat large quantities of compared to meat. If you don’t pay any attention to your protein intake you might find yourself deficient in protein.
Should you turn to vegetarianism for weight loss?
In terms of nutrition and weight loss turning vegetarian won’t solve your problems. Eating more vegetables and less processed foods will. It’s a lot easier to overeat on processed foods than on meat.
The vegetarian diet adds some complexity by making it harder to reach certain daily nutrient requirements. Less complexity is usually better for weight loss.