Also, be aware that when you exercise, your body directly burns away glycogen (a form of glucose stored in the muscles). Fasting depletes these stores, which can mean less available energy for the muscles to use when they need it. This can lead to extreme fatigue and decreased performance. The best fasting tips for athletes are to precede each workout with a low-calorie protein shake designed to deliver creatine, BCAAs, beta-alanine, and other amino acids directly to the muscles as they work them, and then to follow each workout with a whey-protein supplement to replenish depleted nutrient stores in order to speed up the recovery process. These workout supplements won’t add much to your overall calorie count, and will help ensure that your intermittent fasting schedule and your workout regimen aren’t getting in each other’s way.
^ Jump up to: a b c Harris, L; Hamilton, S; Azevedo, LB; Olajide, J; De Brún, C; Waller, G; Whittaker, V; Sharp, T; Lean, M; Hankey, C; Ells, L (February 2018). "Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis". JBI Database of Systematic Reviews and Implementation Reports. 16 (2): 507–547. doi:10.11124/JBISRIR-2016-003248. PMID 29419624.
Some people believe that IF has worked for them simply because the limited eating window naturally helps them reduce the amount of calories they consume. For instance, instead of eating three meals and two snacks, they might find that they only have time for two meals and one snack. They become more mindful about the kinds of food they consume and tend to stay way from processed carbs, unhealthy fat, and empty calories.
Fasting ramps up your stem cell production. Stem cells are like biological playdough — your body turns them into any kind of cell it needs and uses them to replace old or damaged cells, keeping you younger on a cellular level. Stem cells are great for your skin, joints, old injuries, chronic pain, and more. You can try stem cell therapy…or you can just fast.
AN IMPORTANT CAVEAT: Intermittent Fasting can be more complex for people who have issues with blood sugar regulation, suffer from hypoglycemia, have diabetes, etc. If you fit into this category, check with your doctor or dietitian before adjusting your eating schedule. It also affects women differently (there’s a whole section dedicated to that below)
As with any diet, you’ll get the best results if you’re consistent. At the same time, you can certainly give yourself a break from this kind of eating schedule on special occasions. You should experiment to figure out which kind of intermittent fasting works the best for you. Lots of people ease themselves into IF with the 12-12 plan, and then they progress to 16-8. After that, you should try to stick to that plan as much as possible.
You are probably wondering how there could possibly be a benefit to eating less frequently that goes beyond what you are already getting with a ketogenic diet. Restricting carbs and eating enough fat and protein does come with a plethora of health benefits, but when you add intermittent fasting to your lifestyle you can increase energy and reverse aging by harnessing the power of a nobel prize winning process.
If you're looking to lose weight, this isn't a problem. And even if you're happy with your weight, this won't prove to be too much of an issue if you follow the daily fasting or weekly fasting schedules. However, if you're fasting for 24 hours per day on multiple days per week, then it's going to be very difficult to eat enough of your feast days to make up for that.
To make “down” days easier to stick to, Johnson recommends opting for meal replacement shakes. They’re fortified with essential nutrients and you can sip them throughout the day rather than split into small meals. However, meal replacement shakes should only be used during the first two weeks of the diet — after that, you should start eating real food on “down” days. The next day, eat like normal. Rinse and repeat! (Note: If working out is part of your routine, you may find it harder to hit the gym on the lower calorie days. It may be smart to keep any workouts on these days on the tamer side, or save sweat sessions for your normal calorie days.)
Another program called the 5:2 Fast Diet involves eating 5 days a week and fasting for the other 2 days, when women can get no more than 500 calories and men no more than 600. That’s a quarter of the amount you likely eat on the days when you don’t fast. Whether you eat those calories in one sitting or spread them across micro-meals throughout the day is up to you.