Studying appetite is fairly difficult to do, so there’s not a lot of research about it.
However, having a lack of appetite as a vegan, particularly a new vegan, is a commonly reported problem.
So while I can’t give you any clear answers from research, I can summarize the most common things that cause a limited appetite in vegans.
Vegans Typically Eat Way More Volume
When you first go vegan you’ll likely find that in order to eat the same amount of calories as you did before, you have to eat a lot more.
Vegetables are not calorie dense, and yet filling.
Similarly, foods like beans have a lot of fiber and water content, and even a small amount will keep you full for a while.
If your body isn’t used to these foods, it’s going to be a struggle to eat as much as you did. Great if you want to lose weight, but not great otherwise.
If this is your problem, try to focus on more calorie-dense foods like nuts (here are the highest calorie vegan foods), and reduce high fiber foods for a bit. Your body should adapt after a few weeks.
Eating Healthier Will Reduce Your Appetite
This is not specific to being vegan.
For similar reasons to the ones above, whole foods are a lot more filling than junk foods (more water, fiber, etc.).
Additionally, eating a lot of processed foods and sugars essentially ruins proper appetite control. It’s why you can eat a bag of chips and still be hungry.
A lot of people who go vegan all of a sudden start eating healthier. The hormones that control your appetite start to “reset” to normal levels, and of course your appetite goes down compared to what it used to be.
This can be fine, especially if you’re overweight.
The only times it’s an issue is if you’re having trouble eating enough to maintain a healthy weight.
Stress Can Affect Appetite Levels
Being vegan is stressful.
It’s natural to worry about what you’ll eat when you go out, how other people will react, and so on.
It’s also stressful to now recognize so clearly how many animals are suffering at any given moment.
Things like stress and depression can drastically lower appetite.
I wish I could give you an easy answer to fix these problems, but they’re issues that every vegan needs to work through individually. That being said, if there’s anyone you can talk to for support (even an online group), it may be very helpful.
It Could Be Completely Unrelated to Being Vegan
After you go vegan, it’s easy to question if any little thing is caused by being vegan.
In reality, a lot of physical ailments can be unrelated to being vegan.
You might have a cold or the flu, or some other issue that’s causing your lack of appetite.
That’s why if it’s not obvious why your appetite is non-existent, and you’re seeing negative side effects, you need to go see a doctor.
There could be something serious underlying that needs to be addressed.