It seems like a no-brainer; ditching the bacon double cheeseburger for a big green salad will lead to weight loss. This thought process is why plant-based diets are very popular right now, but is a plant-based diet really better for weight loss than a conventional diet containing meat?

What are plant-based diets?

A plant-based diet is one that focuses on foods coming from plants. This includes fruit, vegetables, pulses, grains, nuts, seeds, and meat substitutes.

The term “plant-based” covers any diet derived at least mostly from plants. Standard vegan diets that exclude any foods derived from animals fall easily into this category, as do vegetarian diets containing milk and eggs.

In the broadest sense, you can still tuck into the occasional steak or enjoy an omelet or milk shake, as long as your foods are mostly from plants.

The rising trend in plant-based foods has made it easier than ever to have a plant-based diet. From nut milks to high-tech “nearly meat” products, many vegetarian options are popping up in popular fast food chains and restaurants. Thus, substituting meat for its plant-based equivalent in meals is rather simple and easy nowadays. More traditional vegetarian foods such as beans, tofu and lentils are also good additions to plant-based diet and add needed protein.

Sample plant-based menu

• Breakfast: oatmeal porridge made with almond milk, banana, coffee
• Mid-morning snack: fresh strawberries, whole wheat crackers
• Lunch: seeded bread roll with hummus, grilled peppers and mixed greens
• Afternoon snack: roasted pecans
• Dinner: stir-fried vegetables and tempeh in oyster sauce, noodles, fried egg. Mango sorbet

How plant-based diets help you to lose weight

What happens when people start to cut out meat and how can his help weight loss? Eating plant foods helps weight loss in several ways.

When we avoid meat, we have to stop eating many fatty foods such as bacon, fried chicken and calorie-laden hamburgers, which means these high-calorie foods are no longer appearing on our plates. Taking bacon and chicken out of our Caesar salad immediately lowers its calorie content. Likewise, a vegetarian pizza will usually be lower calorie than one laden with salami.

Many vegetarian meals will have fewer calories than their meat-containing equivalents, however this is not always the case. A veggie burger with French fries will still be about as unhealthy as a plane old burger with fries so we still need to be mindful of what we are ordering.

Another advantage of a plant-based diet is that we end up eating more fruit and vegetables. Fruits and vegetables contain a high proportion of water and a low proportion of fat; thus they contain less energy gram-for-gram. This means that the energy density of our diet is reduced despite eating the same volume of food. This is a key strategy for successful weight-loss: eat the same amount of food but fewer calories.

A third way plant-based diets aid weight loss is that they tend to increase our dietary fiber intake. Fiber helps weight loss because it creates a feeling of fullness that helps people manage their hunger. Have you ever heard of the fiber gap? Most people do not meet dietary fiber intake recommendations, which are about 25 to 30 g fiber per day. Plant-based foods are naturally high in fiber. In particular, the legumes and pulses that are often used in plant-based diets to provide a source of protein are high in fiber. Beans for example, have 14grams of fiber in 1 serving.

Plant-based diets are also naturally lower in saturated fats and cholesterol. If you are trying to lose weight to help with your cholesterol level, a plant-based diet will offer added benefits. Just be careful with cheese and processed vegetarian foods which can be hiding high amount of fat. Plant-based snacks like veggie chips for example, are highly processed and loaded in saturated fat.

Eating out, pot luck dinners and parties pose a problem for dieters. Being presented with an array of delicious food means it’s difficult to hold back! t’s easy to ruin diet plans by overeating, but a plant-based diet can help here. When you avoid foods containing meat, you find that there are fewer foods that you can eat in these situations. You naturally eat less food.

By reducing the amount of high-calorie meaty foods, increasing intakes of low-calorie plant based food, and helping us stay fuller for longer with its higher fiber content, a plant-based diet can help us to eat few calories.

Traditional diets and weight-loss

Ultimately, whether a diet is successful in helping you drop the pounds depends on whether you are able to maintain a calorie deficit whilst following the diet. In this sense, the energy content of the diet is more important than what foods you eat. Lean meats are easily incorporated into many weight loss plans. Some diets, such as the ketogenic diet and any type of low-carb diet rely to a moderate extent on their meat content. While a plant-based high-protein diet is possible, it requires careful planning to implement successfully. Depending on your personal food preferences and circumstances, a weight loss diet containing meat may be easier for you to follow than a plant-based diet.

Pitfalls with losing weight on plant foods

A plant-based diet is not necessarily a weight-loss panacea. There are several pitfalls that may work against your weight-loss goals that you need to be aware of.

Beware of high-calorie plant-based foods

First of all, not all plant foods are healthy or low calorie. For example, while a handful of nuts is nutritious and provides protein in a plant-based diet, nuts have a naturally high fat content and are calorie-dense. If you’re not careful when snacking on nuts you could wind up eating more calories and fat than a cheeseburger.

Likewise, ingredients such as honey or agave nectar are plant-based, yet should be consumed in moderation when trying to lose weight due to their high sugar content. When you are following a plant-based diet, you still need to be aware and read labels.

Some of the snacks we buy in the supermarket may sport a “plant-based” label, but that does not mean it is a healthy snack. Many of the plant-based snacks like chick pea puffs or vegan muffins are loaded with calories, sodium, sugar or saturated fat, making it a food to avoid. It always pays off to closely read the nutrition information to see if the food is going to be a healthy choice.

Keep up protein intakes

A consequence of eating only foods from plants is that protein intakes usually tend to decrease. Lower dietary protein can affect weight loss success, especially for those who work out more.

If protein intakes are too low, the body does not have enough to maintain muscle and muscle mass decreases. This is counter-productive for weight loss! When people lose muscle, their metabolism slows down and its harder for them to lose weight. 

It important that protein intake remains adequate during weight loss. Protein intakes when dieting should remain above 0.36 grams per pound of body weight (0.8 grams of protein per kilogram body weight), and ideally 0.54 grams per pound (1.2 grams protein per kilogram body weight).

Protein also helps you feel fuller for longer. Studies show that part of the reason why high-protein diets help people lose weight is that they don’t feel as hungry and eat less when following their diet.

Focus on risk nutrients

Deficiency can be a concern when excluding meat. Animal-based foods are rich in certain nutrients that can be lacking when switching to a plant-based diet. For example, vitamin B12 is completely absent from vegan diets.

The first signs of vitamin B12 deficiency include tiredness and mental confusion. Although the liver stores enough vitamin B12 for several years, long-term plant-based diets will eventually deplete vitamin B12 stores unless supplemental vitamin B12 is given. Make sure you take a dietary supplement containing vitamin B12 or eat foods enriched with B12 if you cut out all animal foods.

Other B-vitamins including thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3) and vitamin B6 are found in meat, and could be lacking when going meat-free.

Minerals are often limiting in plant-based diets. Meat, eggs and dairy products are good sources of minerals such as iron, zinc and calcium. Iron and zinc can affect how you’re feeling: iron deficiency causes tiredness, while zinc deficiency impairs the immune system. The iron found in meat is absorbed much better than from plant-based sources such as whole grain cereals and green leafy vegetables, so you need more than from meat. Calcium deficiency in adults means the body cannot maintain its bone mass and puts people at risk of fractures.

When you follow a plant-based diet, pay close attention to the following nutrients to make sure you get enough:

• Protein
• Vitamin B12
• Thiamine
• Riboflavin
• Niacin
• Vitamin B6
• Iron
• Zinc
• Calcium

Will you lose more weight on a plant-based diet? The science weighs in

Evidence showing that plant-based diets help people maintain a healthy weight comes from large-scale studies. A well-known population study in Europe, called EPIC, investigated whether there was a difference in body weight between meat-eaters, pescatarians, ovo-lacto-vegetarians and vegans.

The study used data from 38,000 participants in different countries across Europe. Overall, meat-eaters had the highest BMI of 24. The BMI of pescatarians and ovo-lacto-vegetarians was 23, while vegans had the lowest BMI at 22. Depending on your height, a BMI difference of 2 is approximately 8 to 12 pounds (4 to 6 kg). This study shows that vegans and vegetarians are more likely to have a lower BMI than their meat-eating counterparts.  

Head-to-head comparisons of diets allow us to compare how effective they are at achieving weight loss for people who make the switch to a plant-based diet.

One group of researchers pooled the results of 12 different weight loss trials that all compared weight loss with a plant-based diet or with a diet containing meat. Over 1,000 participants took part in these trials, and their weight loss was followed for an average of 18 weeks. The participants following a vegan diet lost 5 pounds (2.5 kg) more than meat-eaters. Vegetarians lost around 3 pounds (1.5 kg) more than meat-eaters. This analysis provides conclusive evidence that a plant-based diet is a little better for losing weight than one that includes meat.

The Verdict

Eating a plant-based diet is a valid strategy to help you lose weight. Eating mainly plant foods lowers the overall calorie-density of your diet and the higher fiber content promotes a feeling of fullness. In social situations, avoiding meat lets you eat less.

Be aware of the pitfalls of a plant-based diet: lower intakes of protein, B-vitamins especially vitamin B12, and minerals. Overall, research shows that people following a plant-based diet lose more weight than when they follow a diet with no restrictions on meat intake, so if plant based sounds like your speed then it’s a good option for weight loss.