The human body has the ability to digest both plants and animal flesh and obtain nutrients from both. The truth is that all the nutrients we need can be obtained from plant foods. Moreover, these plant-derived nutrients are often available in greater abundance and are more readily absorbed in the system than are nutrients obtained from animal products. Too, they have the advantage of being without the harmful health effects that nutritionists are now attributing to our consumption of animal products. For vegans with special dietary needs, fortified foods and supplements can further reinforce their needs.
Be consistent and eat well. Without either one you are going nowhere in your fitness endeavors. If you don’t consistently workout and eat well you won’t look near how you want to. The consistency in the gym builds muscle while burning calories. Eating well helps fuel that muscle growth from lifting as well as promote fat loss from proper nutrient and caloric intake. Removing one or the other won’t kill you but you won’t look and feel your best. If you aren’t using drugs, you need to be patient and consistent over the years to really build a quality physique, it doesn’t happen over night.