[MOVSM]

The latest article from Starting Strength should be the definitive refutation of veganism for men--becoming strong requires lots of calories, good quality protein and vitamins, all things deficient in a vegan diet. And because you are a man with a lot of muscle that requires a lot of food, this may be very difficult.

Quote:

Deficiencies
There are a number of deficiencies that can occur in an animal-free diet that are important for proper physiological function. Vegans need to make sure they're getting enough omega-3 fatty acids (250 mg of combined EPA and DHA minimum) to counter a larger omega-6 intake. Since nuts and seeds only contain the omega-3 ALA, and ALA is not efficiently converted into EPA and DHA, they will either need to supplement with microalgae, buy fortified products, or eat enough foods with a low omega-6 to omega-3 ratio.

Creatine supplementation is a good idea for strength training, whether vegan or not. It's especially helpful for vegans, since they have lower amounts of creatine in their muscles compared to those who consume meat. Creatine has been shown to increase energy production in skeletal muscle, thus, assisting in developing strength and muscular hypertrophy.

A number of micronutrient deficiencies can be found in a meat- and dairy-free diet, as well. These include: Vitamin B12 for red blood cell count, calcium and vitamin D for bone health, iron for energy production, zinc for immune system and metabolic function, vitamin A for vision and other functions, and iodine for thyroid hormone production.

The Realization
You might now be realizing how this diet might complicate a few things. A truly committed individual can make it work by eating lots of oats, peanut butter, bread, pasta, rice, soy, nuts, seeds, tofu, tempeh, fruits and greens, and supplements/fortified foods to eliminate any deficiencies. To make progress in the big lifts (squat, deadlift, press, and bench press), one will have to get enough quality protein and calories by being as meticulous as possible. Without significant planning, little progress can be made as a novice trainee without some voodoo.