I am a triathlete and wondering about wether bp coffee (e.g. coffee with butter + coconut oil) is sufficient as a pre-workout "snack" to prevent katabolism when doing Intermittent Fasting?
I am not aiming for the long distance but my bike workout today was around 3,5 hrs in a fasted state with only the bp coffee before.
Afterwards, I always do carbs.
No, my opinion is that it's definitely not enough to prevent muscle catabolism. Fasted exercise is a fantastic tool for people that are trying to lose weight, as well as being handy for general fitness - where you'd wake up, work out, and then have breakfast. When you are already fit, and are training for something like a triathlon, you want to fuel your body appropriately.
After about 1 hour of strenuous or active exercise, and when you plan to do more -- long distance running, cycling, etc -- you've entered into a zone of exercise beyond normal - definitely more of an athlete. At this level, you should generally try to get something like 30-60g of simple or complex carbohydrates, and liquid or solid - both instances depending on what's comfortable for your particular sport.
This is why "sports drinks" are so popular -- the basic science for consuming sugar at this point is correct, but the garbage they push on normal people and kids what want to be athletic is pretty evil.
So, my suggestion for you specifically is:
Eating small amounts of carbohydrate dense, real foods will help to ensure that you are not accessing any of your body's muscle glycogen stores, thereby conserving muscle.
When I go for long bike rides, I just carry water and fruit with me - it's the easiest thing. I don't cycle for cycling training, so I just get enough to not hamper my other muscle-growth pursuits. In your case, you want to be able to workout for training at the intensity you need that day, but without losing muscle. Small carb, dense snacks will help.
The answer is going to be "it depends." Working out fasted is awesome. It does a lot of good things for us, including autophagy. If you are well adapted to burning fat, and have enough fat reserves, maybe you can get away with a long endurance workout.
A bulletproof coffee before a workout is wonderful for getting ketones going and quickly, and I can last for hours without eating - but that's for fasting days for me. When I workout, I tend to sip the bulletproof coffee between sets. Maybe one sip between each set or something like that.
If you're going for a long endurance workout, you'll work from your glucose stores at first, which will create a nice amount of lactic acid. This will get recycled back by your liver into glycogen which you'll burn again, so while that happens you may be slightly out of breath, or feel the burn, but you'll get a second wind from it.
The larger your skeletal muscles, the larger your glycogen stores are, and the longer you'll be able to go. (You'll also obviously be burning some of the ketones from the coffee as well, but the issue to get at is how soon will you deplete glycogen and get into gluconeogenesis.)
As your glycogen stores run out, ketones will rise as fat stores release their fuel, and you'll burn more and more ketones and fats, your muscles then become slightly insulin resistant and stop burning glucose even if some is available in the blood in order to spare it for red blood cells and brain cells. At this point, you're only burning ketones and fat.
As long as you can produce/ingest enough fat/ketones, you'll be able to keep going - if you can't, or aren't fat adapted, you'll "bonk out." However, your red blood cells and brain cells will continue to use what glycogen/glucose is left in your blood and liver. When this gets low enough, you'll signal cortisol to create glucose by catabolizing whatever protein is around, and if not, it will take it from muscle tissue. So the trick is to ingest some glucose as you you bike, but not enough to stop ketone production. That means very small amounts, and take in more ketone generating fats (coconut, MCT, etc.)
So maybe have a bulletproof coffee before you go, and have a second one with you on your bike that you just take sips from as you feel tired. Maybe you can throw in an egg in it instead of a tiny bit of glucose so your body has a bit of free protein to convert to glucose, or maybe a teaspoon or two of sugar, but not enough where you can taste it. Experiment and see what works best for you.
Type 1 diabetes and Intermittent Fasting 3 Answers
Bulletproof Coffee on Renegade Diet? 4 Answers
Butter in coffee.. and intermittent fast 7 Answers
Hack my 6 Week Plan 1 Answer