What I Learned After Fasting For 46 Hours

6 min read

The Bulletproof Points

  • Fasting for two days at 7% body fat is a terrible idea
  • This was probably due to limited fuel availability, even in fat stores
  • Fasting for 18-22 hours however, isn’t an issue yet

Fasting Through The Lockdown

My latest diet has been a life-saver, and I’m only slightly exaggerating. It’s been a happy distraction from all the cataclysmic world events floating around. This has been a chance to do a deep dive into the diet world, play guinea pig, and test myself against a few fat loss strategies. 

So far I’ve tried intermittent fasting, carb cycling, OMAD, targetted keto, carb backloading, all to varying success. Since I’m near the end of the diet, I figured there was no harm in taking on a two day fast. 

I’ve done it once or twice before, and it’s…fine. I lost some extra weight, maybe half a pound of fat, with the rest being water. But I like cooking and eating, so I initially didn’t try and include it in the weekly fast circuit. 

Trying it yesterday put me in a different ballgame. I lost 2.4kg, near-identical to last time. Unfortunately, I’ve put that all back on today, so it hasn’t really made much of a difference there. I’m well into the single digits of body-fat, and that made it a painful experience. 

I trained as usual on the day of the fast, felt reasonable for a few minutes, then quickly lost all capacity to move for the rest of the evening. The next day was equally mind-numbing. Interestingly, I wasn’t hungry at any stage of the fast. Just dead on my feet. It’s pretty evident I pushed the experiments a little too far.

Can Extended Fasts Get Rid Of Stubborn Fat?

My goal for the two day fast was to put the metabolism under some extra stress and really tap into stubborn fat stores. If you’re not clued in, stubborn fat is generally around the lower abs and thighs, and is always the last to come off. The difficulty is part genetic, part nutrition. If genetics aren’t great, then it’s going to need the kitchen sink of diet strategies. In this case, an extended fast seemed like a great idea.

The complete lack of energy makes it pretty worthless as a stubborn fat solution. But it makes perfect sense due to my low body fat percentage. Simply put, the longer a fast goes on, the more the body starts relying on stored energy. Everything runs out, as metabolism shifts through its list of priorities. This would be liver glycogen, then moving onto muscle glycogen, then fat and protein stores. As a keto fanatic who’s been dieting down for 8 weeks, the liver and muscles are empty. And since I haven’t got much fat left, there’s nothing left to keep the tank running. 

Obviously the body can start to catabolise the muscle tissue at this stage, but it’s an inefficient process that doesn’t exactly provide a lift in energy. You’ll still feel like you’re on the verge of starvation.

Fasting Shouldn’t Cost You Health And Performance

I’m a bit of a fasting fanatic, but this is where I’d draw the line. Not just because I don’t really want to start shedding muscle. It’s also just an unhealthy and stressful state to be camped in. As a rule, I’ve never sacrificed my brain state, because it’s poor to begin with.

So by doing this fast, I’ve become more aware of the effects that fasting can have on lean dieters. This isn’t an issue for people at healthy weights, although you might run into similar issues if you’re insulin resistant and particularly bad at mobilising fat stores. To solve this, I could probably get away with a zero carb day instead. Practically just meat, oils, and eggs. I wouldn’t be explicitly fasting, but there’s nothing there that’s going to hit insulin and suppress fat loss. 

As far as my normal 20-23 hour fasts go, they’re absolutely fine. I feel great in the morning, hit the home gym at the tail-end, and get the big meal in just as I’m starting to drop. What I will do, is start to raise calories back up towards maintenance. I’m happy with my shape right now, so there’s no point in pushing further. Especially if I just get switched over to zombie mode.

Next up on the self-experiment checklist is the carnivore diet. It’s picking up some pace in the diet scene now, with a lot of good science behind it. Just like keto, the rules are quite straightforward. All you have is animal products, and even dairy gets a bit of a bad rap. So you’re left with red meat and eggs for the most part. It’s fascinating, so I’ll be trying it out over the next few days. Just like the extended fast, my diet is already hitting similar notes, but I still have to cross an extra bridge to get there.

Hey, I’m Sama, a natural bodybuilder who’s bought into the perks of keto and intermittent fasting. Why? When combined, the boosting effect on mental energy is unrivalled on any other diet. And the fat loss isn’t bad either. 

I’ve got a ton of recipes, guides and insights covering both diets, and you check them all out on my blog.




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