 Hey, everybody. Dr. O here. So what is the 5-2 fasting protocol, or what is the 5-2 diet? So for five days of the week, you eat normally, and you don't restrict your calories. Your goal should be to eat your regular maintenance calories, which you determine by figuring out your total daily energy expenditure. Your goal should not be to eat everything that isn't nailed down. We'll come back to that. But then on the other two days of the week, you drastically reduce your calorie intake to about one quarter or 25% of your daily needs. This typically leaves you with consuming about 500 calories on your fasting days. The fasting days are not supposed to be consecutive. You want at least one day between your fasting days to recover and rebuild. I'll show you how I do mine on Mondays and Wednesdays. The 500 calorie fasting day is actually backed up by some of the earliest research on intermittent fasting. You might actually be surprised to realize how much of the fasting research is actually looking at modified fasting programs, like modified ADF and the 5-2 diet, where the study participants do consume some calories on their fasting days. There's also a ton of evidence emerging for the fasting mimicking diet. So it's no surprise that this actually works pretty well. But I do want to show you a few ways to make this plan work even better for you later on in the video. I'm also going to share why I am updating this video now. I've never actually done the 5-2 fasting protocol when I first made my fasting course. But now I'm using it. I'm using the 5-2 diet and it has been working great for me. I now understand the pros and cons a lot more because I'm living it. I'll share how I tweak it to fit my needs, just like I did with alternate day fasting later in the video. So this is the original 5-2 plan here. You see how it doesn't matter which two days, but on Mondays and Wednesdays, you'd be consuming 500 calories and then the rest of the week, the other five days, you'd eat your regular maintenance calories. So this is the original 5-2 plan. So if you're someone that normally consumes 2000 calories per day, this would mean you'd eat these 500 calories. But you can eat closer to 600 calories per day if your normal intake is actually quite a bit higher than 2000 calories per day. So it's supposed to be a reduction down to 25% of normal. This is a fine protocol to try. It's similar to the 500 calorie days that we talked about in the modified alternate day fasting or hybrid ADF video, but let's see what the science has to say. It was actually quite a bit of it. So what does the science say? The effect of intermittent compared with continuous energy restricted diet on glycemic control in patients with type 2 diabetes, a randomized non-inferiority trial. So this is a 12-month trial. The average food intake of the participants before the trial was 2100 calories per day. So there was the continuous energy restriction group. They were on a diet every day, so they cut their calories by 30%. So they averaged 10,300 calories per week, which was an average of 1,471 calories per day. So doing that for 12 months, they lost 11.02 pounds or five kilograms. The 5-2 diet group was in a 75% deficit two days per week, and then they ate normally the rest of the week. So they actually averaged consuming 11,500 calories per week, which averaged out to 1,643 calories per day. And they lost 14.99 pounds or 6.8 kilograms. So they ate an average of 172 more calories per day, and they lost 3.97 more pounds of weight or 1.81 kilograms. So I'm all for any program that allows you to lose more fat while eating more food. So that's a pretty good combination. So here's a quote from this trial. Intermittent energy restriction is an effective alternative diet strategy for the reduction of hemoglobin A1C, something they were really serious about in this trial, and is comparable with continuous energy restriction in patients with type 2 diabetes. So that's a pretty good trial to get us started. Let's look at this next one. The effects of intermittent and continuous calorie restriction on body weight and metabolism over 50 weeks, a randomized controlled trial. So this, again, was a 50-week trial that found that the 5-2 diet was more effective than continuous calorie restriction for weight loss. So the intermittent calorie restriction group, they ate normally on those five days and then they went into a 75% deficit two days per week. And over these 50 weeks, they lost 7.1% of their body weight. The continuous calorie restriction group, they were in a daily 20% calorie deficit and over the time of this trial, they lost 5.2% of their body weight. So to be honest, I would much rather be on a diet two days a week compared to seven days a week if I can get the same or better results, which is what this trial showed. But what's actually going on here? Why are people losing more weight in the same calorie deficit or if they're actually eating more? I think this study here can help explain the answer. So intermittent energy restriction attenuates the loss of fat-free mass in resistance-trained individuals, a randomized controlled trial. So this study found from Bill Campbell's lab found that a two-day refeeds, so for two days going back up to your maintenance, not even overfeeding, but two-day refeeds preserve fat-free mass and resting metabolic rate during energy restriction compared to continuous energy restriction, at least this was in resistance-trained individuals. But this form of calorie cycling where you get all your dieting done in two days appears to minimize metabolic adaptation, and you know how I feel about calorie cycling. So you're losing more weight because you're burning more calories, or at least you don't start burning fewer calories along the way. That's what this study talked about, this preservation of your metabolic rate. And I'll show you another study soon that will do the same thing. So on top of this, I do think ketones are involved as well. Most people would generate some ketones if they only ate 500 calories in a day. Multiple studies have shown that ketogenic diets do increase metabolic rate. Now it might only be 50 or 60 calories per day, but that adds up, and other studies actually show higher numbers between 200 and 300 calories per day. Ketones also allow you to waste some energy. Look at like a ketone test strip, a urine test strip. You can tell you're in ketosis because you're literally peeing out the ketone body called acetoacetate. You're literally peeing out fuel. So I'll talk a lot more about this in my upcoming course on low carb and keto diets, but I think this is part of the puzzle as well. All right, so here, another study, or this review, sorry. What does the science say here? A meta-analysis comparing the effectiveness of alternate day fasting, the 5-2 diet, and time-restricted eating for weight loss. So this review looked at seven different intermittent fasting studies that use the 5-2 diet. So I won't talk about what they found with alternate day fasting, but they did find that it was more effective. So we'll come back to that. So these are the studies, and there were 743 participants in total. The studies ranged from 2 to 26 weeks. So during these studies, the weight loss ranged from 1.8% up to 6.84% of body weight, while these study participants were consuming 25 to 30% of their normal calorie intake. So these studies actually ranged in calorie intake from 500 to 730 calories per day on their fasting days, depending on the study. These studies all showed positive results, but the weight loss wasn't mind-blowing. Like I just said, alternate day fasting worked better. This makes sense. The calorie deficit isn't very large. If you're following the 5-2 diet, 5 days a week you're eating normally, and 2 days you're restricting your calories. The 5-2 method is more of a slow and steady weight loss method that focuses on sustainability, in my opinion. You will need to use a more aggressive diet, like alternate day fasting, if you want to see faster results. Or you can find ways to make the 5-2 diet more aggressive. So let me show you that. So here is a more aggressive form of 5-2. You completely fast, so notice on Monday and Wednesday you're consuming zero calories. You completely fast 2 days per week. That is a more aggressive alternative. This makes the most sense if you want to lose fat more quickly, or if you want to fast clean. So you know how much I love 36 hour fast. This would incorporate two 36 hour fasts per week. A true 36 hour fast will have a greater impact on your blood glucose and insulin levels than eating 500 calories a day would, especially if you're eating carbs. It will also enhance the health promoting benefits of your fasting window by increasing autophagy, decreasing inflammation, gut healing, etc. And here is yet another way to do 5-2. I call this one the relaxed 5-2, and a lot of people really like this one. So you'll notice that you do have your fasting days on Monday and Wednesday where you're not eating any calories, and then Tuesday, Thursday, Friday you're eating at maintenance. But we save those calories. Rather than eating 500 calories on our fasting days, we move them to the weekend. So on Saturday and Sunday, you would be eating in a 500 calorie surplus. So that's why I call this a relaxed 5-2, because you can eat more on the weekends. That's another benefit of consuming zero calories on your fasting days is you can bank them up. Save them for either the weekend or save them for heavy training days, which is what I do. This is the best of both worlds in my opinion. You're going to get more mileage, more benefit out of your fasting days by keeping them clean. This method also takes advantage of the calorie-cycling methods that I love. I think it's very important to mix it up and kind of keep your metabolism guessing, whatever that means. So eating zero calories on your fasting days then allows you to overfeed by 500 calories on two of your eating days, and you can choose which two. This also might make the plan more sustainable for the long haul, and that's really all that matters in the end. If eating a few more calories on Saturday and Sunday will keep you going, then it's going to be worth it. So most people beat themselves up and feel bad if they eat more on the weekend, but this relaxed 5-2 approach allows you to make it part of your plan. You're not losing the war here. You're actually doing what you're supposed to do in this situation. But why? Why overfeed by 500 calories instead of eating at maintenance? I'm certainly not telling you have to. You can do 5-2 any way you want, and I'm not the fasting police. What's the science say here? Lept, there's multiple studies I could have shared, and I shared several of them in the calorie-cycling section. But leptin responses to overfeeding, relationships with body fat, and non-exercise activity thermogenesis. So this study here showed that adipocyte, or fat cell, leptin expression was up-regulated with overfeeding, and leptin concentrations increased. So why do we want to increase our leptin levels? Well, leptin is a hormone released by fat cells. It basically tells your brain how much stored fuel you have on your body. So leptin helps with satiety. If you have a lot of leptin, your brain won't make you as hungry. So it helps with satiety. It helps with sex hormone production. Dropping leptin levels are the reason that people that get super lean might start to have issues with losing their menstrual cycle, et cetera. So satiety, sex hormone production, and also it keeps your metabolic rate humming along by promoting energy expenditure. If you have a lot of leptin, your brain will subconsciously motivate you to move. All cool stuff. So if you're always in a calorie deficit, your metabolism will respond by making that deficit the new normal. This is why if you go into a 500 calorie deficit, you'll lose a pound a week for a while, then half a pound a week for a while, and then zero pounds. That's because your metabolism has adapted. So keeping your metabolism guessing by getting into a surplus every once in a while appears to be valuable. So here's my current plan. I told you I updated this video because I'm using it now. So you'll see that I fast on Mondays and Wednesdays. So I used to fast four days a week, and then three days a week. Now I'm down to fasting two days a week. And I do eating a surplus on Tuesday and Thursday. And then you see that I walk every day. And then when I say, where it says exercise, those are my heavy lifting, heavy trading sessions. So I've actually lost 27.8 pounds and counting since I switched to a 5-2 plan a few months ago. So why did I switch? 8 ADF alternate day fasting will always be my first love. But I'm too lean for three or four 36-hour fasts per week now. I mean, it's a great problem to have. I was showing signs that it was too aggressive and I don't want to lose lean mass, so I backed off. I love this plan because I still get to do some 36-hour fasts, which do make me feel the best. But I also get a four-day diet break every week. So when I wake up Thursday morning, I have four days in a row where I'm either eating in a surplus or eating at maintenance. I'm not on a diet at all. I use my calorie surplus days though. I don't save them on the weekends like the Relax 5-2 protocol. I use them for the days right after my fasting days. This helps me recover from fasting and it also sends an anabolic growth signal to my body. I want my body in building mode as soon as possible after a long period of fasting without protein. So I credit this with why my lean mass is still going up while my fat mass is going down. I've now added a total of 19 pounds of lean mass in the last two and a half years and I'm just a few pounds away from weighing what I did when I was 11 years old. I'll make a video that kind of celebrates that when I get there. The lowest number I know of. So I mentioned that I get the four-day diet break. So this 5-2 plan also gives me a four-day psychological break from dieting until I'm ready to dive back into a calorie deficit again on Monday. This four-day period where I'm eating well makes the plan more sustainable. I love psychological breaks from dieting. It's why I did so well with ADF. This is probably why I'm still going strong after two and a half years. I'm not showing any signs of slowing down. But are there also metabolic advantages? Let's take a look. I'm actually surprised I've never talked about this study in any video I've made, but this is a neat one. So what does the science say? Intermittent energy restriction improves weight loss efficiency in obese men. The Matador study. So maybe you've heard of this one. Matador is short for minimizing adaptive thermogenesis and deactivating obesity rebound. I love how they think of cool study names. So there are 51 males with obesity. The continuous group dieted for 16 weeks straight. The diet break group, they dieted for two weeks on, two weeks off. So they ate at maintenance during their diet breaks. So both groups were in a 33% calorie deficit for 16 weeks. It's just the diet group took longer to get there or the diet break group because they took these two-week breaks. But the results really might surprise you. So let me show you the data here. So the continuous calorie restriction groups, they were in a 33% deficit for 16 weeks straight. They lost 20.28 pounds or 9.2 kilograms of weight. 86.96% of their weight loss was fat, which was great. Why did they get such a high number? Because they were obese. If lean people did this, it would have cost them more lean mass. This is neat. The resting energy expenditure went down 749 calories per day after they adjusted for changes in fat mass and fat free mass. That is a lot of metabolic adaptation, which is why diets are less and less effective the longer you go. But now let's look at the diet break group. So these are the ones that dieted in the same deficit for two weeks, then took a two-week break and then came back to it. So they dieted the same number of days. They lost 31.08 pounds or 14.1 kilograms of weight. 87.24% of their weight loss was fat. Their resting energy expenditure went down 360 calories per day after adjusting for fat mass and fat free mass changes. So they had more weight loss with less of a drop in metabolic rate. Signed me up. Before you ask, this huge difference in weight loss cannot be explained by extra weight loss that was occurring during the diet breaks. This was a very tightly controlled study. They were eating at maintenance. And so the mean weight change during the diet breaks was 0.0 kilograms, plus or minus 0.3 kilograms. So they really were weight stable during their diet breaks. So they didn't get more weight loss because they were losing a little bit of weight during these diet breaks. Another important note. There are other studies that show that diet breaks don't work. Most of these other studies didn't control food intake, like the Matador study did. And they allowed for what's called ad libitum feeding or food intake during diet breaks. Ad libitum means at one's pleasure as much as one desires or to the full extent of one's wishes. So if you're on a diet break where you're trying to maintain your weight, you are probably not eating at one's pleasure. So I hate to break it to you, but the more you go off the rails on your eating days, the less this plan or any other plan will work for you. So the conclusion. Greater weight and fat loss was achieved with intermittent energy restriction. Interrupting energy restriction with energy balance rest periods may reduce compensatory metabolic responses and in turn improve weight loss efficiency. So I think that's the key there. When you take dates, breaks from dieting or diet breaks, then you get less metabolic adaptation. And we've talked about that again in the calorie cycling video series. So I do think that makes the most sense. Now this study was looking at longer breaks, right, to eat diet breaks. But even they said they have no idea what the best length of a diet break is. But I think a four day diet break every week during your program ticks a lot of the same boxes. At least that's why I think it's working so well for me right now. Another important point before we finish up here. What should you eat on your 500 calorie days, right? So how can you maximize the benefit of your 500 calorie days if you do traditional 5-2? So I don't do 500 calorie days, but if you do, you have two options that will both work depending on your goals. Option one is to focus on protein. This will turn your 500 calorie fasting days into protein sparing modified fasting days. So I covered that method in the modified ADF video or the hybrid ADF video. So go back to that one. This option is best if you want to preserve as much lean mass as possible because you're giving yourself a bunch of protein on your fasting days. Option two is kind of a new one that I've been playing with. So option two is to get most or all of your calories from fat. This is called a fat fast. So I will definitely be doing a video about fat fasting in the future. I've heard about fat fasting years ago, but I was never lean enough to think it was a good idea, right? Fat doesn't stimulate insulin and mTOR the same way that carbs and protein do. So fat can fly under your metabolism's radar. So fat fasts are best if you want to maximize the health benefits of fasting while still getting some calories. So what type of fat should you use? I've been experimenting with these fat fasts a lot more now that I'm so close to my goal weight, right? At some point I will be losing lean mass if I'm not careful and I monitor it closely, but I still have to have these things in my back pocket. So here are my pro tips for fat fasts. Number one, you can use any fat you want technically, but I recommend using MCT oil or medium chain triglycerides. So MCT oil is a great fuel source for the body, right? The C8 form of medium chain triglyceride is called caprylic acid. So it's the most ketogenic of all the MCT oils and will boost your blood ketone levels, right? Studies have shown that your ketone levels will go up even if you're eating spaghetti and sauce as long as you have MCT oils to boost them. So I personally do use the Bulletproof Brain Octane since it's 100% C8. I've used a lot of other ones, but that's what I'm using right now because there are other medium chain triglycerides like C10 and C12, but C8 is the one that your body turns into ketones the best. You can also try an MCT powder if MCT oil causes GI distress, and again, if you have too much of it, it can cause some serious bathroom related issues. And if that's the case for you, you may want to either consume less of it or switch to an MCT powder. Speaking of ketones, you can also go straight to the source and take exogenous ketones on your, again, fasting or modified fasting days. I've used several exogenous ketones recently, but my favorite is called keto start. So it only has 52 calories and it causes my ketone levels to jump more than when I use MCT oil. But the cool thing is why not do both? Combining MCT oil and exogenous ketones like this product, no affiliation, but like this product will crank up your ketones and take your modified fasting days to the next level. So if you're going to use a fat fast, those are the things I'd recommend that you do. So play with both protein and fat of the approaches and see which one works best for you. All right, so what are the pros where the cons? So the pros of the 5-2 fasting protocol. Great solution for people who struggle to stick to a diet seven days per week, right? You only have to stick to a diet two days per week. This typically from a poundage standpoint, right? It's typically a great approach for a male that has 30 or 40 pounds to lose or a female that has 25 to 30 pounds to lose. If you have more weight than that to lose, then I'd probably guide you to the alternate day fasting. If you have less weight than that to lose, you'll have to start to get less aggressive. This can be a great transition for someone who's working towards alternate day fasting, right? If you're easing into things, this is also a nice transition as someone becomes too lean to continue doing alternate day fasting or they're increasing their training frequency. So they need to eat on more days per week. This is why I made the switch myself. So what are the cons? I mean, the biggest one is you just won't lose weight as quickly as the approaches we've already discussed, like alternate day fasting, 4-3, Monday, Wednesday, Friday fasting, or the hybrid or modified ADF approach. So you won't be in as big of a calorie deficit at the end of the week. Also, you will miss out on some of the health benefits of fasting if you're consuming 500 calories on your fasting days. So give it a try and let me know how it works for you. All right, so that's the 5-2 protocol. I hope this one helped. Have a wonderful day. Be blessed.