All The Pretty Diets

Keto, vegan eating, and intermittent fasting from a fitness perspective.

Anyone with a reasonable grasp of 21st century etiquette knows that one does not discuss one’s dietary choices in mixed company. You’re much better off discussing less polarizing topics such as politics, religion, and gender assignment.

But I’m not known for my politesse, so let’s talk diets!

Today, we’ll take a look at three popular modalities—keto, intermittent fasting, and vegan eating—with an eye on how they can impact your workouts.

If you’re curious about any of these diets, I encourage you to try them. Best case, you find a life-changing way of eating. Worst case, you make a couple urgent bathroom visits and you find a diet that doesn’t work for you—but you learn how your body reacts to certain foods.

Keep in mind that no single way of eating is perfect for everyone. If anyone tells you otherwise, they’re selling something. Don’t be a sap.

Ketogenic dieting

Originally created to treat epilepsy, ketogenic dieting is low-carb eating dialed to 11. Not only do you reduce carbohydrates, but you also keep protein very low.

The idea is to minimize foods that readily introduce glucose into the blood. (Protein converts to glucose in the absence of carbs.) Without glucose, the body shifts to an entirely different energy system called ketosis, where the liver converts fat into chemicals called ketones, which you use for fuel.

I’ve met a few people who swear by keto, but most of those people also eat donuts or cake. When I question these deliciously contradictory dietary choices, they claim they just do keto on weekdays or they’re “partially” keto. This strategy doesn’t make a ton of sense to me given it takes several days (at least) to achieve proper ketosis. Once you arrive there, I don’t think it works like a light switch. (Ketoians, let me know if I’m mistaken.)

All this said, I’ve spoken with enough keto followers to believe that some of them must be doing it by the book and having success.

The medical community is investigating keto as a solution for several health issues beyond epilepsy, like Alzheimer’s and other neurological issues. If that’s why you want to try it, obviously speak with your doctor.

Ketogenic dieting + exercise

Keto advocates claim that the diet is ideal for endurance athletes because your body prefers to burn fat during long, less intense efforts. If that’s you, here’s a diet to consider.

However, your body needs glucose and glycogen to properly execute hard efforts such as high intensity interval training, sprinting, or just beating your cycling buddy up a hill. Since these efforts are crucial for any athlete who want to improve performance, if you’re looking to get faster or stronger, keto probably isn’t for you.

Intermittent fasting (IF)

There are a few variations of IF. Some have you fast for days. Others have you fast for hours. Most people opt for hours because, well, if you need to know the unpleasant downside of fasting for days, just watch a few episodes of Naked and Afraid.

One popular take is 16/8 intermittent fasting, which means you have an eight-hour feeding window every day. Frankly, it’s not that tough. You just need to stop eating after dinner and hold out for a late breakfast.

Advocates make some pretty wild health claims about IF that are pretty easy to poke holes through. That said, Endocrine Reviews recently published a paper suggesting that a restricted feeding window might help reduce the risk for obesity, diabetes, and cardiovascular diseases, so that’s a space to watch.

If you’re prone to becoming hangry, practicing IF might be a good way to train your body to tolerate a fasted state without ripping anyone’s head off.

Intermittent fasting + exercise

Mostly, it’s fine. If you eat properly during your feeding windows, you should have enough glycogen to get you through most activities. There are a couple caveats though. If you exercise for more than two hours at a time, it behooves you to eat before working out—and certainly during—so that you have enough fuel to avoid bonking.

Also, if you feel chronically sore or have a hard time recovering, squeezing all your protein into shorter timeframe may mean you’re not getting enough, keeping in mind that you can only process around 30g of protein at a time. Consider adding a protein shake or yogurt outside your feeding window.

Vegan eating

Ethically, vegan eating is lovely. Animal products take a big toll on the environment. Veggies, not so much. No one denies that going animal-free helps the planet—that said, crops like California almonds don’t do the earth any favors either, so nobody should cast stones.

The health benefits of the vegan lifestyle aren’t black and white. Sure, you avoid processed meats, which are terrible for your health, but a lot of vegans replace their crappy beef salami with crappy textured soy protein salami, which isn’t a huge upgrade. No matter what food groups you eat, it’s important to make educated choices within those groups.

If done right, the vegan diet can potentially be healthy from a cardiometabolic perspective. But, again with the caveats: It’s super important for vegans to focus on nutrients that most people get from animal products, including protein, vitamin B12, iron, and vitamin D.

Vegan eating + exercise

Hard exercise depletes your nutritional resources. Where a moderate-exercising vegan might get the nutrients they need from whole foods, a seriously athletic vegan probably needs to add supplements, particularly protein. Luckily, there is no shortage of great plant-based protein choices out there, including Vega and my alma mater, Beachbody.

Mix and match nutrition

It’s important to try new things. If you’re down, take these modalities for a test spin. But when you experiment, pay extra attention to your physical performance. Maybe note on your fitness tracker (Strava, Garmin, etc.) that you’re trying a particular diet so that you can analyze shifts in your fitness.

Also keep in mind that, just like religion and Legos, mixing-and-matching is allowed when it comes to diets. If you find a facet of a diet that you like, take it with you. For example, many vegans ultimately become flexitarians, meaning they go plant-based most of time, with the occasional piece of meat. (Not sure what they do about almonds.)

Instead of ending with my usual self-satisfied quip, I’d like to open the conversation up to you. I’ve started a discussion forum on the topic of diets. You’ll find it here.

Since I’m just starting this Substack, there might be crickets in the forum for a while. It’ll be embarrassing (for me), but whatever. Maybe if a bunch of you jump in, I’ll send of you a free pair of socks or something.