The idea that you need any animal products to be healthy or strong is a myth propagated by the milk and meat industries. The biggest land mammals hypos, elephants, giraffes are herbivores. Plants are loaded with amino acids, the building blocks of protein. Pulses in particular have around 20% protein and the average human needs only about 40 grams of protein per day.

We are opportunistic omnivores, we can digest meat for survival but we don't have to in an age when we're well past the survival stage.

As for skinny vegans, no diet is healthy by default if it's not balanced and you don't pay attention to the nutritional needs of the human body. I highly recommend that you research vegan nutrition if you're considering veganism. Vegans who eat a varied diet of whole foods such as plants, fruits, nuts, seeds, algae and fungi are healthy. Ethical vegans, who become vegan purely from an animal cruelty perspective, tend to be careless about their own health and end up eating a bunch of processed shit giving all vegans a bad stereotype. There are way more sick omnivores, the top omnivore causes of death are due to ingestion of animal products, but hey let's focus on the skinny vegans.

There are plenty of examples of healthy and strong vegans competing at the highest levels. Here's a few:

Patrik Baboumian the world strongman champion

Tim Shieff the world freerunning champion

Richard (aka Vegan Gains) body builder

Sam aka the vegan gardener

Look up on youtube "vegan body builders" for more.