Are You Diet Fluid?
I'm a "dietary agnostic." Or, if I were to use more current social parlance, you could call it "diet fluid." In other words, I don't believe any one type of eating is inherently better – from a health perspective – than another.
Further, as a student of human physiology and biochemistry, I know that our bodies are wonderfully plastic. Give the body hard strength training and our muscles, connective tissues, and bones adapt. Give the body meditation and mindfulness practices and our brains adapt.
Similarly, people can quickly adapt to high fat or high carb, all meat or no meat, as long as whatever style they choose is executed intelligently.
I've also spent 30 years as a coach. In coaching, you have to put your own biases aside. I call this "client-centered coaching" and it focuses on questions like: Who is my client? What do they want? How can I help them get it? This instead of foisting "my way" onto them.
So, if a client wants to go carnivore... great! But let's make sure they do it right to avoid the inherent problems associated with cutting out all plant-based foods (i.e. certain nutrient deficiencies, lack of fiber, eating too few calories, struggling in the gym, etc).
If they want to keto... cool! Just let's make sure they do it better than the average person who does keto, so they avoid the inherent problems associated with cutting out carbs (similar to the problems above).
If they want to vegan... awesome too! But it's important to make sure they do it thoughtfully to avoid the problems with eating only plant-based foods (different nutrient deficiencies, risk of low protein intake, risk of too few calories, etc).
Heck, even a "balanced, mixed diet" comes with its own set of concerns that have to be navigated and strategized around. As I always say to clients, it doesn't matter how you want to eat, I can help you do it better, in a healthy way, that increases your probability of reaching your goals.
So, when it comes to muscle building and performance, any of these diets can work as long as you:
1 Train appropriately for your goals.
Easier said than done since there's a lot of misinformation out there about how to train for your goals. Plus it's difficult to force your body to adapt to a training stimulus after the newbie gains are gone. This takes a mix of correctly-designed programs, hard training, and appropriate recovery.
2 Eat enough food.
No matter what your macro split is, or what diet du jour you've decided to follow, you need enough calories to support hard training and muscle growth.
When you eliminate entire food groups it's an added challenge to get all the calories you need. So, if you've decided to eliminate animal foods (or plant foods, or carbs, or whatever) you have to be more diligent about making sure you're eating enough of everything else.
3 Eat enough protein.
If you train hard, with adaptation in mind, there's no getting around the fact that you have to get enough dietary protein.
Again, eliminating animal foods makes this more challenging, but not impossible. As with calories, you just have to be more diligent. You might even need to write things down and track them over time to ensure you're not fooling yourself.
4 Adjust your training based on your diet.
In some cases, if you've decided to follow a specific diet that restricts certain nutrients – or that requires you to fast for extended periods – you may have to adjust your training to accommodate this. This could mean lowering volume and/or intensity because of your dietary selection. Or, in some cases, increasing it.