 Hey everybody, Dr. O here. Welcome to one of the most important videos that I've ever recorded or ever will if you want to lose weight, right? In this video, we are gonna answer the question, how many calories should I eat to lose weight? And if you're gonna go on a diet, this should be the first question that you want to answer. But as you've seen in the previous lessons, you can't really answer this question until you answer a couple of other questions first. That's why I've asked you to determine or estimate your body fat percentage and estimate your total daily energy expenditure. So in this video, I'm gonna show you why we need those things to actually answer this question. How many calories should I eat to lose weight? Every situation is certainly unique, but science can give us clues that can give us a great place to start. And that's what I'm super excited about. I wanna show you a study that actually can help us answer this question. All right, so you really, this is the real question. How many calories can you cut before you start to lose lean tissue? I say this all the time, you're better off losing nothing than losing muscle because it's so metabolically active. What's the point of losing weight if your metabolism drops? You're gonna gain the weight back and probably more. So we wanna lose as much fat as possible while holding on to as much lean mass as possible. We wanna be aggressive on our diet, but not too aggressive where it starts to do more harm than good. And you will leave this video with that number for yourself. It's all based around this study. So what does the science say? A limit on the energy transfer rate from the human fat store in hypophagia. So it's a couple, energy transfer rate is basically saying how much energy can your body fat provide from the human fat store, from your body fat stores in hypophagia when you're not eating to your maintenance calories. This is one of the most important studies I have ever seen as a dieter or as a teacher. It truly does allow you to know how much energy your fat can provide each day so then you can determine how many calories you can eat or need to eat. So if my fat provides a certain number of calories then I have to provide the rest or I'm going to lose lean tissue. It actually comes from this, what's known as the Minnesota starvation experiment data. They made a mathematical model after using this study here. It was called the biology of human starvation, but there was 36 volunteers. They put them on a 1,570 calorie a day diet for six months and these volunteers lost 25% of their body fat. Using this data, they created the mathematical model that we're looking at here today. So let me read part of the abstract to you and then I'll demystify it for you. A limit on the maximum energy transfer rate from the human fat store in hypophagia is deduced from experimental data of underfed subjects maintaining moderate activity levels and is found to have a value of 290 plus or minus 25 kilojoules per kilograms per day. I will translate that into calories per pound. A dietary restriction, which exceeds the limited capability of the fat store to compensate for the energy deficiency results in an immediate decrease in the fat free mass. That's the key. In cases of a less severe dietary deficiency, the fat free mass will not be depleted. This, what this is saying is, if you know how much body fat you have, you know how much energy it can give you a day. If you make up the difference, you will lose fat without losing fat free mass, which is lean tissue like muscle. If you do not make up the difference with the calories you're eating in a day, you will immediately start to lose fat free mass and we don't wanna do that. We only want to lose fat. We wanna hold on to our lean mass. That's the key to the entire program that I'm building. All right, so look at these numbers here. You see where I did the calculations. I converted kilojoules per kilograms per day into calories per pound per day. Ballpark, that's gonna be the number 29 to 34. So every pound of fat you have on your body is gonna be able to provide 29 to 34 calories per day. I usually stick with the number 30. I wanna err on the side of being less aggressive because I wanna help you preserve lean mass. You know, I've told you my story in multiple places. I lost 100 pounds while barely losing any lean mass and then I actually lost 165 pounds while increasing my fat free mass, while increasing my lean mass by 15 pounds. So using this data was one of the most critically important points. So that's how we're gonna err on the side of caution. But what's so cool about this is we no longer have to guess how many calories we should be eating on a diet. Now, should I just eat 1,200? Should I eat 1,500? You don't have to guess anymore. We're asking your body and we're gonna get that answer. So I think this is gonna be a huge gain changer for you. I really do. All right, because that's exactly what it's allowing us to do. How aggressive can I be on a diet before I start to lose extra lean mass? Yes, you might lose some because you're carrying a smaller body around. The only downside to this strategy though is you do need to know how many pounds of fat are on your body and that's why I've already asked you to determine your body fat percentage. So go back and do that if you don't know that number. So let's look at some real world examples. So here we have a 300 pound man with 40% body fat. He would have 120 pounds of fat on his body. A 150 pound woman with 30% body fat. She would have 45 pounds of fat on her body and a 200 pound man with 12% body fat. He would only have 24 pounds of fat on his body. So let's look at these examples one by one. So here we go back to our 300 pound man. If he has 120 pounds of fat on his body, take that number times 30. His body fat store can provide 3,600 calories per day. His maintenance calories is 2,560 calories per day. This means that this person could not eat anything and would have no problems and that's why if you have a lot of weight to lose, you can do things like alternate day fasting. So for this person, that's what I would recommend. I would recommend alternate day fasting where you have a day where you eat and a day where you consume zero calories or as close to possible. So he has so much fat on his body that if you look down here on the right side, he would have to become a heavy exerciser before his total daily energy expenditure could get above that 3,600 calorie number where he might start losing lean mass. So I would absolutely advocate for a fasting protocol like alternate day fasting for this person. So the answer to how many calories do I need to eat in a day for this person is really zero. Now I don't recommend fast longer than 36 hours because you will start to lose lean mass but at least every once in a while, this person would be safe consuming zero calories. But now we get into some gray area. A 150 pound woman with 30% body fat, she has 45 pounds of fat on her body which means that her body fat can provide 1,350 calories per day if you take that number times 30. Her maintenance calories, you see here, female, 150 pounds, sedentary, 30% body fat. Her maintenance calories is 1,678 per day. So if you take 1,678 calories, minus 1,350. So we're saying, here's how many calories she needs in a day. Here's how many calories her body fat can provide. The answer is 328 calories. So if this person needs to make sure they're eating at least that much. Now I'm not saying to eat 328 calories a day, that would be ridiculous. But I would recommend if this person wanted to do like an alternate day fasting protocol, I would make sure that on those quote unquote fasting days that she would still be consuming somewhere around 300 calories a day, which is perfectly fine. There are modified alternate day fasting programs where people consume up to 500 calories a day. That'd be perfect for her. So the first person, 300 pounds, alternate day fastings fine with zero calories. This person, I would recommend alternate day fasting still because it would help her lose weight very quickly. But I would recommend that she had a few hundred calories a day, probably of protein because protein is filling and also helps reserve lean mass. Now on to the next one, a 200 pound man that only has 12% body fat. So this guy has 24 pounds of fat in his body. Take that times 30 and you get 720 calories. So his maintenance calories is 2,513 calories per day though. So 2,513 minus the 720 that his body fat can provide leaves us with 1,793 calories. So whatever type of diet this person goes on, they should be consuming about 1,800 calories a day to maximize their fat loss while minimizing lean mass. If they go on a diet that's more strict than that, they will start to lose more lean mass than required. If they go on a diet that's less aggressive, that's perfectly fine. They'll just lose weight slower. This is just teaching you that sweet spot. So for this person, it's 1,793 calories per day. So I would not recommend alternate day fasting. I wouldn't recommend something like a 5-2 protocol. This person, if they wanted to do any sort of fasting, I would recommend time restricted feeding, probably a 16-8 protocol where they're eating in an eight hour eating window and then fasting for 16 hours. And you don't need to fast at all, but these would just be, I'm just showing you that there are different ways to get to these numbers. All right, so those are some really important examples. You can determine this information for yourself. So let's take a look at now it's your turn. Determine your weight by using a scale, take multiple, make sure you take measurements same time of day, no clothes, just went to the bathroom maybe, and then take it for several days and get an average. So that's how you determine your weight. Your body fat percentage, go back to the video lesson about how to determine your body fat percentage with nothing but a tape measure with the US Navy body fat calculator. So you know your weight, you know your body fat. So let's say that you weigh 200 pounds and you have 25% body fat. Now take your weight times your body fat percentage to figure out how many pounds of fat on your body. So if you weigh 200 pounds and you take that times 25% or take that times 0.25, you would get the answer 50. So this person here weighs 200 pounds, 25% body fat. They have 50 pounds of fat on their body. And the last thing for this slide, take your fat pounds times 30 and that's your fat calories. So he has 50 pounds of fat times 30, that would be 1,500 calories. This person's body can provide 1,500 calories of energy per day. But now you have to know your total daily energy expenditure. So I just taught you how to do that. So let's say that for this person, his total daily energy expenditure is 3,000 calories per day. So total daily energy expenditure, 3,000 calories minus fat calories, 1,500 calories equals the calories you should eat every day. So this fictitious person and maybe it's similar to you should be eating 1,500 calories a day at minimum. So this, so like it says here, alternate day fasting is a great option if that number is zero or a negative number. But in this situation, no, you're going to want to consume at least 1,500 calories per day to maximize fat loss while minimizing lean mass loss. I'm not saying you can't diet more strict than that but you will lose more lean mass. I'm not saying you can diet less strict than that. If he eats 2,000 calories a day, he will still lose weight. He will just lose it more slowly, perfectly fine. All right, so a few warnings here. These are estimates, right? So you have to play with this and if things aren't working the way that you want, then make some changes. You can be more aggressive. You can lean on the more aggressive side. If you're lifting weights, your sleep is in order and your stress is in order. If you do the kind of things that help you hold on to lean mass, then you can be even more aggressive than this number will show you. Just remember that the typical goal should be to lose about 1.5%, 0.5% to 1% of your body weight per day. I don't say a pound per week or two pounds a week. If you weigh 100 pounds or 400 pounds, those numbers should be different. So you wanna be losing weight at a clip of about 0.5% to 1% per week. If you're losing it faster than that, you're probably being too aggressive. If you're losing it slower than that, then that's fine, but maybe you could be a little bit more aggressive. So keep those things in mind. All right, so the size of the calorie deficit is really what's gonna determine how much lean mass you lose. But gotta keep in mind, these are just estimates, so that's why in the last video I recommended, get your total daily energy expenditure figured out, but then actually test it. You eat that many calories for a week or two and see if your weight goes up, goes down, or stays the same. If your weight stays the same, then it truly is your maintenance calories. All right, so this answer is a critically important question. How many calories should I eat every day on a diet to maximize fat loss while minimizing lean mass loss? I truly hope this helps. Have a wonderful day. Be blessed.