The question of whether plant or animal protein is “better” is more nuanced than it sounds. Both have a place in a healthy diet, and framing them as direct rivals misses the point — it’s more useful to look at how they actually differ and how to combine them sensibly.

Amino acid profiles

Protein is built from amino acids, nine of which the body can’t produce on its own and must get from food — these are the essential amino acids. Animal sources of protein — meat, fish, eggs, dairy — generally contain all nine essential amino acids in proportions close to what the human body needs, which is why they’re called complete proteins. Most plant sources are missing, or fall short on, one or two amino acids: grains tend to run low on lysine, while legumes run low on methionine. There are exceptions, though — soy, quinoa, and buckwheat all provide a full, adequate set of essential amino acids on their own.

Digestibility matters just as much

Beyond amino acid content, how much of that protein the body actually absorbs and uses matters too. Animal protein is, on average, somewhat more digestible than plant protein, partly because fiber and antinutrients like phytates in plant foods can slow protein breakdown in the gut. Cooking, soaking legumes, and sprouting grains all measurably improve the digestibility of plant protein, narrowing the gap with animal sources.

Combining sources solves the completeness problem

The classic way to get a full amino acid profile from plant foods is to pair sources with complementary gaps over the course of a day. The best-known example is grains plus legumes: rice and beans, bread and hummus, buckwheat and lentils. The lysine that grains lack is abundant in legumes, and vice versa for methionine. It’s worth noting these foods don’t need to be eaten in the same meal — current research suggests the body can draw on amino acids from different meals across the day as long as the overall diet is varied enough.

The nutrients that come along for the ride

Choosing between plant and animal protein is rarely just about protein in isolation — each source brings its own package of other nutrients. Red meat is a strong source of easily absorbed heme iron and vitamin B12, which is essentially absent from plant foods. Fish supplies omega-3 fatty acids. Legumes and whole grains, in turn, bring fiber, a range of phytonutrients, and less saturated fat than most meat products. That’s why shifting toward a mostly plant-based protein intake calls for attention to specific nutrients — B12 above all, along with iron and, for some groups, omega-3s.

Does the body need different amounts?

Total daily protein needs don’t actually change based on where the protein comes from — they’re driven by body weight, activity level, and other individual factors. But because some plant sources are less digestible and have incomplete amino acid profiles, people building a diet mostly around plant protein are sometimes advised to aim slightly higher on total protein intake to offset the difference.

The practical takeaway

There’s no need to pick one protein source exclusively — what matters to the body is the overall mix of amino acids and nutrients it gets across a day, not any single food. A diet built on a variety of plant protein sources — legumes, grains, nuts, seeds — combined with animal foods to taste and preference, usually covers all the bases without extra effort. Anyone eating a fully plant-based diet should pay particular attention to varying their protein sources and to supplementing vitamin B12.