Do vegans need to eat more? Plant-based diets, digestion speed, & nutritional density

Question

Does vegan food have a lower nutritional density? In other words: Do vegans need to eat more to get adequate levels of nutrition than they would on an omnivorous diet?

Meat tends to sit in the intestines for a long time. Is this because meat has a higher nutritional density, and that is why it takes the body longer to digest it, or is it because meat-eaters consume less fiber? It seems plant-based foods digest quicker, but is this due to lower nutritional density or to higher levels of fiber intake in plant-based diets?

Answer 1

On a weight basis, plant-based foods (especially whole foods) generally have:

• ✅ more vitamins
• ✅ more minerals
• ✅ more dietary fibre
• ✅ more water
• 🔻 less calories
• 🔻 less protein
• 🔻 less fat

Some people who adopt a plant-based diet find that they need to eat more food (more mass and more volume) in order to reach the same feeling of satiety (fullness) that they did on their earlier diet.

I'm not aware of any evidence that meat stays in the digestive system longer than other foods.

Answer 2

It really depends on which foods are we talking about. The variety of vegan foods is very large. There are several thousands of plants and vegan products that you may consume, they all have different nutritional (and calorie) densities.

I would say it always depends what you compare them with. When you do a comparison to omnivorous diet, do you count all the same (vegan) plants/products as a part of the omnivorous diet? Then they will overlap.

Watermelon and lettuce may have very low nutritional density, while seeds/nuts/grains/beans/avocado may have very high.

To answer the question whether vegans need to eat more food, I'd say it really depends with what you compare with. You can be a vegan who eats only salads and raw foods OR a junk food vegan that drinks cola, eats fries with ketchup and (vegan) mayo. These are of course extremes, but you get the idea.

Eating a balanced diet composed of variety of foods is probably the best way to go, and I wouldn't worry much about the quantities. If you are still curious, you can check out Daily Dozen app (both available for android and ios). There is a check-list of daily food recommendations for optimal health. It should give you an idea for the quantities.