Many proponents of flexitarianism will claim it can help with weight loss:

  • Mark Bittman created VB6 (Vegan before 6) after his doctor told him to lose some weight.
  • Dawn Jackson claims her Flexitarian Diet can help those struggling with obesity.

However, anyone selling a diet book is gonna tell you it can help with weight loss.

What does the science say?


Since there’s no set in stone interpretation of what makes a “flexitarian” a flexitarian, it can be hard to prescribe any specific benefits to the diet.

This is a concern Emma J. Derbyshire brought up in a review of semi-vegetarian diets in Frontiers of Nutrition. Derbyshire states that before any formal recommendations can be done on flexitarians, “official definitions of these diets are needed.”

You need to know exactly what you’re researching before you can make heads or tails of what’s going on.

However, weight loss itself has been studied a lot, so we aren’t completely stumbling in the dark here.

As we address in our guide How to Lose Weight (The 5 Rules of Weight Loss), our bodies obey the Laws of Conservation of Energy and Thermodynamics:

To lose weight, we need to burn more calories than we consume regularly.

It’s about as close to fact as we can get in nutrition science.

Here’s the thing about meat: it’s actually pretty calorically dense, especially when you compare it to fruits and vegetables.

This is 200 calories worth of sliced turkey (thanks to wiseGEEK):

Here is 200 calories worth of Saltine crackers (which are vegan):


When comparing a plate of meat to a handful of crackers, you might think: “Steve, there’s no way those crackers will satisfy me, I’ll need to eat more food,” then you’d be right.

It’s why focusing on foods that fill you up without being overloaded with calories can help with weight loss.

Let me share one more example:

This is what 200 calories worth of broccoli looks like:

So, YES, if you replace your meat lovers pizza, chicken parm with pasta, and bacon cheeseburgers with  mostly fruits, vegetables, and other whole plants, you’ll most likely lose weight.

It comes down to total energy (calories) consumed!

This is something we bring up throughout our Guide for Plant-Based Diets: be careful about replacing calorie bomb meat products with heavily processed junk food.

You might end up with the same amount of calories (if not more), which means you’ll have no weight loss.


Because from a protein perspective, meat can be a great source of nutrients.

Let’s compare chicken against black beans, since legumes (beans) are some of the most protein-dense plants you can eat:

  • 100 grams of black beans: 22 grams of protein, 339 calories, 63 grams of carbohydrates (16 grams of which are fiber).
  • 100 grams of chicken breast: 30 grams of protein, 165 calories, 0 grams of carbohydrates.

The same size serving of black beans has less protein, twice as many calories, and more carbs compared to chicken.

This isn’t to say you can’t get adequate protein from plants (we tell you exactly how to do it in our guide to vegetarianism), it’s just something you have to appropriately plan for!

All this to say: you can lose weight on a flexitarian diet as long as you burn more calories than you eat consistently.

If semi-vegetarianism actually helps with that, great! If not, no biggie, just try another path (here’s what I personally do).

Let me just say that if you’re trying to lose weight and wondering if a flexitarian diet is the solution, I’m proud of you for at least THINKING about different nutritional strategies that might align with your lifestyle and goals.

Lots of our coaching clients come to us with all sorts of different fitness questions, like what to eat and how to exercise, proving we all start from unique situations. The important thing is that you’re beginning to ask questions and looking for answers.

If you want help on your journey, we’re here for you. Our 1-on-1 Online Coaching Program partners busy people just like you with a coach who will get to know you better than you know yourself.