Mike is an accomplished ultramarathon runner in his mid 40s. Here’s his approach.
My diet, when being strict:
Morning usually starts with two cups of coffee with heavy cream, MCT oil, a tiny bit of Stevia, and about a teaspoon of honey. (that’s for both cups) I usually drink one cup while I eat a few strips of bacon, a couple strawberries, a handful of almonds, and some pieces of cheese. This might vary slightly depending on what we have. (maybe blueberries or a few grapes, although they’re very carby and I try not to eat more than a couple at a time) I then take my second cup of coffee with me to work and drink it over a couple hours. Occasionally I’ll have and egg instead, cooked in butter with some cheese, avocado, a little salsa, and maybe some other veggies if we have them like mushrooms or onions. (I have made my eggs scrambled with heavy cream but got a little sick of them that way)
For lunch it’s often a combination of “snacky” items like more cheese, celery with cream cheese or almond butter, beef jerky, a frozen “fat bomb” that my wife makes with cream cheese and berries, basically whatever is in the fridge in small amounts. Some days I’ll have a very fatty spinach salad with tomatoes, celery, mushrooms, cheese, avocado, and dowsed with olive oil and a little vinegar. Some days I’ll add a little lunch meat, tuna, or salmon.
Dinners are often a piece of meat (steak, pork chops, salmon, lamb, etc) cooked in butter and/or olive oil along with a vegetable, also cooked in butter/oil, usually with cheese on it to further fatten it up. My wife likes to make a casserole with cauliflower (in place of potatoes) mixed with heavy cream, mushrooms, onions, chile peppers, chicken or ground beef, with LOTS of cheddar cheese on top. We will, from time to time, get low-carb tortillas and make Mexican food of some sort using various meat, peppers, cheese, avocado, salsa, topped with sour cream. Some of these items I will add olives to, which I like, while my wife will be more inclined to add/use coconut products, which I hate.
Once I had been very strict (even no honey in my coffee or grapes and before we bought the low-carb tortillas) for a couple of months I slowly reintroduced some slighty carb-rich, or even the occasional very high-carb “treat”, back into my diet through the addition of a beer about 4 or 5 nights a week and a fresh, hot cinnamon roll on Saturday mornings, along with maybe one meal out where I just would eat what sounded good. (sushi, Mexican, pizza) As long as I didn’t do multiple things for more than a day or two it seemed to have little to no effect on my general well-being and overall energy levels. (a couple of times I overdid it on back-to-back days and started feeling poorly, which went away quickly after returning to a more strict diet) It also seems to have no lasting after-effect if I take in carbs while doing a long and/or intense run, or immediately afterward. (it is nice to sometimes just have a Coke and not care that it contains more than half your carbs for the day!) I do, however take in much less than before still.
Sometimes I’ll snack in the afternoon on some nuts or get another fat-loaded coffee or plain unsweetened tea but I don’t generally feel that I “need” a boost, more often I just need a few more calories in just to maintain some weight. Also, I am adding salt to things (I never used to) and taking sodium, potassium, and magnesium daily.
I have gone through phases where I’m not as strict and probably have around a hundred grams of carbs a day, but as long as I’m training hard it’s seems to have a little effect. Even then I figure I’m only taking in 20 to 25% of what I used to take in daily since I seldom eat regular tortillas, chips, bread, rice, potatoes, pasta, all former staples of my diet.
So, it may seem a little boring but that’s about it except for the occasional new “keto friendly” recipe we might find online. Seems to be working pretty well for me and I think the real key, at least in my case, is that I’m working out at least 8 to 10 times a week (running 5-6 days, weight lifting 3-4 days) which seems to keep things humming along nicely. I really don’t know if I’m fully in “ketosis” all the time but I make adjustments daily based on how I feel and how much I weigh. (I have a tendency to drop a couple pounds in a day if I’m not careful since I’m not always hungry, what a problem to have!)