Why Am I Gaining Weight On A Plant-Based Diet? 7 Common Reasons!

By Lily •  Updated: 03/25/21 •  8 min read

If you have gained weight recently while on a diet, you aren’t alone. Unfortunately, being on a plant-based doesn’t guarantee you will shed the extra pounds.

I learned this from personal experience. When I went vegan about 4 years ago, I thought I was going to lose weight, but I didn’t, and I was extremely disappointed.

Back in those days, I did not understand that diets have nothing to do with weight-loss and that essentially all that really matters is calories in and calories out.

In this blog post, I will break them down the reasons why you might be gaining weight on a plant-based diet. Plus, you will learn how to avoid and overcome these weight-gain pitfalls. Let’s get started!

gaining weight on a plant based diet

1. Not Understanding A Plant-Based Diet And/Or Your Body

Plant-based doesn’t equal a healthy diet, all plant-based means is that you don’t consume animal products. French fries from Burger King can be considered plant-based, however I would never advise anyone who is trying to lose weight to eat them. 

Plant-based also doesn’t equal low calorie. So the first mistake is thinking that just because you cut animal products from your diet, you can now eat as much as you want and not gain weight. I will talk more about this in detail throughout this blog post.

When you go plant-based, you replace certain foods with others. For example, you might replace meat with rice. In turn, this will lead to you eating more carbs than protein. 

Everybody has an ideal Macro Ratio, meaning that certain people perform better when they eat more protein, while others perform better when they eat more carbs. 

So if you are one of those people that perform better if they eat more protein, and now you are eating more carbs, your body will not work as well as it used to. To determine your ideal macro ratio, click here to take the quiz.

Having said all this, of course a plant-based diet can be healthy and it can be low calorie. In fact, being plant-based facilitates a healthy and low-calorie diet

However, you need to know how to do it the right way.

2. You Are Eating Plant-Based Junk Food (Processed Food)

Believe it or not, there is such a thing as plant-based junk food. In the store, you can find vegan chips, vegan ice cream, vegan frozen dinners, vegan cheese, etc. 

All of which are packed with calories, preservatives, and artificial ingredients. So just because you become plant-based doesn’t mean that you will for sure lose weight. 

If you want to learn more about the psychology of why we crave junk food, do yourself a favor and Click Here to read this awesome blog post I wrote. 

So what should you be eating then? First, you should continue to not eat meat and dairy as this is a step in the right direction towards losing weight. 

Then, your plate should be mostly filled with food that is not processed, such as vegetables, fruit, beans, sweet potatoes, etc. In other words, food that comes from the earth and not a factory, whole foods.

3. You Are Including Too Many Meat Substitutes In Your Diet

Could meat substitutes be impeding your weight loss efforts? Meat substitutes, they are becoming so popular nowadays, and it seems like every week I see a new product at the grocery store.

Meat substitutes are processed food, so even though they are plant-based they are not necessarily healthy. 

Meat substitutes, also known as mock meat, can contain as part of the ingredients tons of oil, non-organic soy, salt, and preservatives.

Eat tofu or tempeh instead (make sure you buy organic), or make your own black bean burger or chickpea falafel. Plus you will be saving a lot of money by not buying mock meats!

I’m not saying to eliminate mock meat from your diet forever.

I buy Beyond Meat burgers to cook in the fire when I go camping, however it should be something we enjoy sparingly. Cutting down on processed food will aid in your weight-loss journey.

4. You Are Eating Over-Sized Portions of Healthy Foods

Do you sometimes ask yourself “Why am I not losing weight if I am eating healthy?” The problem might be that you might be eating too much healthy food and therefore consuming more calories than you should be if you want to lose weight

For example, you might be eating salads all the time, and that’s great! However, what toppings and dressings are you adding to it? Did you know that 1 ounce (37.8 g) of seeds is about 160 calories! Did you know that 1 tablespoon of dressing is about 75 calories? Did you know that 1/3 of a cup of dried cranberries is about 125 calories

Toppings might seem insignificant, but they are not! Keep this in mind next time you are fixing yourself a salad.

Do you like fixing yourself a peanut butter and jelly sandwich? I don’t blame you. They are delicious! However, did you know that a tablespoon of peanut butter has about 100 calories? The problem is that peanut butter has a lot of dietary fat. It has about 16 grams of total fat.

I’m not saying that peanut butter is unhealthy. Heck! I eat it! All I’m saying is that you need to watch how much you are eating because the calories can quickly rack up.

One last example. You might be sipping on liquid calories. You need to realize that unless you are drinking water, tea, or coffee, your drink most likely has calories. 

Do you like drinking kombucha? That’s healthy, right? Well, besides from all the sugar that it most likely contains, a bottle can have up to 120 calories!

In conclusion, you might be eating more calories than you think you are! If you are counting calories to lose weight (which you should be), you need to include all the toppings, dressings, condiments, and fats that you are eating into your daily calorie count.

5. You Have a Health Condition You Are Unaware Of

If you truly believe that you are doing everything right to lose weight, and yet you are still unable to, then there is a very real chance that you might have an underlying health condition.

I very common health problem that causes weight gain is an under-active thyroid, especially among older women. It happens when your thyroid gland does not produce enough thyroid hormones, which leads to the metabolism slowing down.

Other common causes that can cause or prevent weight-loss are diabetes treatments, steroid treatments, Cushing’s syndrome, and Polycystic Ovary Syndrome (PCOS).

If you believe that you are suffering from any of the health conditions mentioned above, you should seek medical attention.

6. Why You Might Burn Fewer Calories on a Plant-Based Diet

If you are new to a plant-based diet, you might still be adapting to the lifestyle and food restrictions. And because you are still learning, you might not be eating the right foods or the correct amount of food. This can lead to you feeling fatigued and tired.

Feeling less energized can then lead to you exercising less than you were before you were a plant-based. And if you exercise less than you will burn fewer calories and can start gaining weight depending on how much you are eating.

You must educate yourself well before becoming plant-based so that you don’t experience fatigue right after transitioning from a meat-eater diet.

7. You Are Lacking Important Vitamins and Nutrients

Skimping on protein, B12, iron, healthy fats, etc. can lead to you not feeling your best and even feeling fatigued (the same reasoning applies as #6 above).

It is crucial that continue to get all the vitamins and nutrients that your body needs so that it can function at its best. 

According to Doctor Melinda Ratini, some of the reasons your metabolism can slow down are: you are not getting enough calcium, you are cutting too many carbs, or follow a high-fat diet.

If you think you might be low on certain vitamins or nutrients, ask your doctor to have a blood test done on you. A blood test can detect these kinds of issues.

Keep in mind that if you are committed to following a plant-based diet to lose weight, you might need to invest in various supplements. My favorite multi-supplement is Ritual (it’s vegan friendly).


Seeing the numbers on the scale go up can be very disheartening. However, realizing why you are gaining weight is the first step in the right direction. 

I hope that you were able to identify the reason(s) why you are gaining weight on a plant-based diet from the ones I listed above.

What reason do you feel is causing you to gain weight on a plant-based diet? What everyday changes will you make to get back to your ideal weight? 

Let me know in the comment section below and don’t forget to share this blog post with a friend!


Hi, I'm Lily! Like you, I have struggled with my weight. It was not an easy journey but I was able to lose 40 pounds and have kept it off for 14 years. My goal is to share with you all the research, tips, and tricks that I have learned over the years to help you lose weight also.