if fat loss is your goal it doesn't matter whether you are fasting or not identifying what is going to keep your metabolism high should be priority number one now subcategories of that priority number one would definitely be maintaining muscle adequate protein things like that right so that all falls under that high metabolism category we want to avoid doing anything that dramatically slows down our metabolism so I can jump right in and talk about a really interesting paper that analyzed a 12-hour fast a 36 hour fast and a 72-hour fast to help identify when things kind of slow down and when things speed up let's break it down so after today's video I popped a link down below for a free variety pack of element electrolytes so with any purchase from element you get a free variety pack a sample packs that you can give out a bunch of different flavors to your friends or just keep them for yourself so if you're fasting I'm telling you it is a game changer when it comes down to being able to have something to sip on that isn't going to impact your fast so they have citrus salt flavor they have mango they have mango chili they have lemon habanero just tremendous flavors that are not going to impact your fast as a matter of fact they're going to improve your fast because you're going to be getting those electrolytes in which when you're fasting insulin levels are lower and you're losing minerals so it's a good time to be bringing it in so anyway pop that link down below and that's going to get you that free variety pack when you try them out trust me it'll change how you fast so the study that we're looking at was published in the British Journal of nutrition and it was a little bit of an older study but I have a newer study that I want to cross reference it with so that we can understand some more stuff what they ultimately found when they investigated a 12 36 and 72 hour fast is that a 36 hour fast actually increased metabolic rate what that means is that actually increased the metabolism 12 hour fast actually kind of lowered it a little bit or didn't have much change in a 72 hour fast was practically no change from the 36 hour fast so what this is telling us right here is that above 36 hours we actually don't get much additional benefit outside of of course some fat burning but we're not increasing our metabolic rate now does this mean that everyone should just go out and do as many 36 hour fast as possible no not at all because that's not really practical in fact a lot of people watching this video that might even be scary to embark on a 36 hour fast in the first place but what we do need to do is look at another paper that was published in the American journal of clinical nutrition and this one looked more at just continuous caloric restriction so they had subjects overeat for one week and then they had them go into a deficit quite significantly a 50 caloric deficit for about three weeks and then after three weeks they had them do a two-week caloric refeed of 50 Surplus what they found is during that three-week caloric deficit they ended up shrinking their resting metabolic rate by 266 calories 108 of which was from what's called adaptive thermogenesis what this basically means is that when they went through extreme caloric restriction they ended up slowing down their metabolism and having a five percent reduction in skeletal muscle mass this happened in literally three weeks now the reason that I mention this is that this is likened to a traditional 16-8 intermittent fasting regimen when people are not paying very close attention to what they eat during their eating window not getting enough calories in under eating and putting themselves in that caloric restriction phase and people lose a lot of weight with intermittent fasting right out the gate particularly 16 8. if you analyze their calories most of the time you find they're eating a lot less that does not mean that you're not getting benefits independent of caloric restriction with fasting because you are there are benefits that come from fasting that are completely separate and apart from caloric restriction however a lot of people that are fasting are still restricting calories they're just not necessarily realizing it so the concern is that in three weeks you can be plummeting your metabolism to such a point whereas when we look at this British Journal nutrition study we see well relatively infrequent longer fasts will actually increase the metabolism so we need to find The Sweet Spot here right how do we find that sweet spot where our metabolism does not slow down now with this we should also reference another study that was published in the journal Endocrinology that found that when subjects did three 24-hour fasts on non-consecutive days it also improved their glucose tolerance so I did another video where I kind of broke all these studies down to try to find the perfect frequency of fasting but what we're looking at here is like at what point does your metabolism slow down so with three non-consecutive day 24-hour fast there were improvements in how the body utilized glucose but there weren't these issues with metabolic slowdown so what we find here is that if you are fasting essentially daily early and putting yourself in a caloric restriction phase it takes about two to three weeks for your metabolism to slow down whereas if you were to fast maybe two days per week but like a 24 hour fast or one day a week at a 36 hour fast you can actually increase metabolic rate because it's such a shock to the body and it's not chronic caloric restriction you actually get this benefit but I don't expect everyone to do that one day a week that's not what I'm getting at what I am suggesting is that if you're doing daily 16 8 you have about two weeks before you need to say hey I gotta take a break or I gotta reduce my number of fasting days and it's okay to do this in a fashion where you're like sprinting and then you're taking a break sprinting and taking a break we have to continually sort of shock the body a little bit otherwise you're going to put yourself in this metabolic slowdown this way you can maintain doing this for a long period of time and there was a cool study in cell reports that demonstrated that the longer just in terms of your lifetime that you can adhere to caloric restriction the more fat burning effect the more autophagy and the more heat shock protein effect you can get so you continue to extract benefits if you can make it a lifestyle you cannot make it a lifestyle if you're shrinking your meta metabolism or your metabolic rate forever and ever and ever that's just not realistic you're going to become frail and weak and you're not going to feel good so find a method that works for you but just do not continually fast every single day for longer than about a two week period before you take a break I'll see you tomorrow