Intermittent Fasting: When to Workout

Question

Anyone using intermittent fasting know if there is an optimal time to workout (morning vs mid day vs evening), especially with an 8 hour eating window that's in the latter half of the day (say 2-10)? I wasn't sure if there was an optimal time in conjunction with the work out, either for a fat loss / muscle gain perspective?

Answer 1

Gaining muscle

It's undeniable that after fasting for 16 hours (as an example), your body might not be as physically capable as it was a couple hours after a hearty meal. So it might be a good idea to get your weightlifting in during the eating window. After you've had some food, and with at least one protein-rich meal afterwards.

Fat-loss

From a fat loss perspective, I absolutely love going for fasted walks before breaking my fast. Getting up in the morning, chugging some water to get the engine room working, and going for a nice, brisk walk. The longer you extend your fast, the longer the body will use fat stores to replenish energy, and the morning is an excellent time to take advantage of that.

My recommendation

...is to go for a walk before your first meal, having only consumed water. Optionally with some vitamin supplements in said water, but add no calories.

Then time your weight training such that you have had a meal or two, and you can get some protein in afterwards.

Using myself as an example

I've been doing intermittent fasting almost inadvertently for a couple years now. I was recommended to try IF, and when I was trying to schedule my day, I realized that I only had to change one little detail; stop snacking after dinner.

My day goes as follows:

I wake up between 7 and 9AM. I have some water and I take the bus to work.

I get off the bus 2-3 stops before the nearest stop to my work, so I can get a little walk.

I eat my first meal at 11AM. I make it pretty big, but healthy. Usually a large salad, or leftover dinner.

At 1PM and 2PM, I snack on fruit.

At 3PM, I grab some more fruit, and leave work and go to the gym to lift. At this point, my energy is high, my blood sugar is at a stable high, giving me lots of energy for heavy work.

I usually arrive home and will have dinner at around 6PM, and that's my last meal of the day. It used to be I would snack during the evening, but that's the adjustment I made when deciding to try IF. I stopped snacking after dinner, and I haven't since.

This gives me an eating window of about 7 hours, which means I fast for about 17 hours. Following the rule-of-thumb, that means I have 11 hours of my body burning fat exclusively for energy.