There's a joke some doctors like to tell about protein.
"How can you tell if your patient is getting enough? They just walked in through the door."
In other words, if you're moving around normally, chances are you're getting a good amount. It sounds simplistic, but it makes one thing clear: the vast majority of vegans are getting enough protein - and as they all know, it is easy to do without consuming animal products.
But people are obsessed with protein - and how necessary it is for good health and fitness. Tell someone you're vegan, and the obsession gets even more intense.
Suddenly everyone is a nutritional doctor, ready to diagnose you with protein deficiency.
The macronutrient is needed (in sensible quantities) for energy, to build and repair muscle, and process nutrients, among other essential roles.
But having too much leads to its own problems, from weight gain to kidney problems - so where has this idea that more is better come from?
A staple in health-conscious or fitness-oriented individuals, it's claimed that chicken is now consumed in such large quantities that some health and environmental experts believe we're creating an excess protein problem.
Director of global health at the UK Health Forum, Modi Mwatsama says: "There is this perception that protein is good for your health, but I am not sure where that has come from.
"It’s certainly a good marketing ploy."
According to Mwatsama, UK and US adults are actually eating 40-50 percent more protein than needed.
When it comes to animal protein, it can be loaded with saturated fat, cholesterol, added antibiotics, and hormones.
Eating excess animal protein or drinking protein shakes - in additional to your daily caloric needs - can actually make you gain weight. "Meat often means extra fat and also calories," says dietitian nutritionist Kaleigh McMordie.
"And many protein shakes have added sugar to make them taste better. Over time, too many excess calories, no matter from fat, sugar, or protein, will cause weight gain."
In addition, consuming large quantities of animal-based protein can contribute to cardiovascular disease; even what you would consider as 'lean' sources of protein - such as poultry - can be stuffed with additional antibiotics, as well as bacteria, parasites, and carcinogens.
Author of bestselling book Diet for a New America John Robbins argued that 90 percent of factory-farmed chickens are infected with leukosis - aka chicken cancer.
Usually when people are eating too much protein, they're not eating enough carbs. Our brains run on glucose from carbohydrates, and forgoing them can leave us feeling lethargic, as well as experiencing brain fog.
Wellness coach Ken Immer explains: "Brain fog, in general, is also a possibility from too much protein, as a sugar deficit for the brain can cause your brain to actually shrink."
There are other issues connected with low-carb, high-protein diets too, with followers putting themselves at risk of colonic disease due, in part, to low fiber intake, which is essential for digestion and regularity. Fiber sources such as whole grains, vegetables, and fruits should be part of everyone's regime.
On the whole, plant-based protein is a much easier digestible source - and by mixing plant sources of protein, you can ensure your bodies gets what it needs.
But consuming too much of any protein can lead to the buildup of toxic ketones - which are substances made when the body uses its own fat cells for fuel in the absence of carbohydrates.
Isolated plant protein, such as shakes, bars, and powders, can also lead to a number of health issues.
It may sound boring, but it's true - when it comes to health, moderation is important. And that should be a factor in your protein intake.
Next time a non-vegan is a know-it-all about your protein intake because you're plant-based? Politely suggest they need a little extra fiber...