Fasting

 
 

So welcome today everyone how for prime fit nutrition today. I'm really looking forward to sharing with you some very exciting research that's come out about weight loss in particular. So this is part two of intermittent fasting and I gave a talk on part one and last time I talked about what actually is intimate fasting and the different ways of going about intermittent fasting. Is it superior for weight loss compared to other forms of diets? What are the health benefits of intermittent fasting? Like does it increase longevity and should I skip breakfast? And the big question, is it just a fad or does it deserve behind? So I'm not going to go through those as much today, but still lots to, but I'll share a quick recap or introduction for those who can attend. So intimate fasting, it's a form of energy restriction, so it's quite significant energy restriction, restricting about 75 to 90% of what we need from food and drink each day on one to three days per week depending on the region that you do. So these would be like a fasting day. If any of your head about Michael Mosley's approach, you get down to about 500 600 calories a day, and then on the other day there's no restrictions, just ate normally, and there are many, many ways to go about intermittent fasting.


Then we have the old and gold standard for weight loss, which is a daily continuous calorie restriction. And so that's just another form of energy restriction. Generally you restrict energy intake from food and drink by about 25 to 50% so not as significant a, and that might be over a specified time period depending on diet. So that's your very classic conventional dieting. When we compare that conventional dieting to intimate fasting, intermittent fasting, yes, they're all health benefits. It's a Bible, although not necessarily superior strategy for weight loss compared to a continuous daily calorie restriction. That's still benefits, it increase longevity, but it's really only evident in animal studies at this point. And you look more likely to be a healthy weight if you include breakfast. So those are the main take home messages from the last talk. So today what I want to talk about is a bit of nitty gritty deicing. Why is dieting and ng restriction so hard? What are the risks of dieting, energy restriction, intimate fasting? What are the side effects if you run, how does energy restriction affects my appetite, particularly on fasting days? And what's the actual secret to weight loss? That is, it's quite a lot to get through today or I'll try and get through it and have plenty of time for questions at the end.


So let's start by looking at some basics of basics. Metabolism. Is anyone heard this one site around metabolism? Yes. So scientific definition is chemical processes that occur within a living organism in order for it to maintain life, sustain it from life. So we need to supply the body energy to allow all these chemical processes. But how much energy do we need to give out bodies or how much energy do we actually burn each day? And this is what's measured in calories or kilojoules. So calories is technically the American unit of unit of measure energy and kilojoules and Sea Australia. So for every calorie is 4.2 kilojoules. That's where you might see differences on food labels. And the classic recommendation is for adults need about 2000 calories a day, but it's actually quite individual. Does that seem a little reference? So how much energy you any daily and how much will actually burn in a day is determined by quite a few different things that the biggie is our resting metabolic rate. Is this the energy we need for daily functioning? Think about all the things that occur and you don't even think about it. So things like breathing, no more repair and maintenance of your organs and body tissues. So if you were completely the bedrest, this was, this is the basic amount of energy you need just to stay alive. And that's pretty variable, that component, but it's anywhere from 60 to 70% of the total energy that you,


in this physical activity energy that you've burned through bottling movement, it might be incidental like climbing some stairs or it might be planned that only accounts for 20 to 30% of total energy that you've been. And then we have something called the thermic effect of food. Does anyone ever heard that celery is technically a negative food? It takes more to to burn, it actually contains, it's kind of that, that example, you actually do need a fair bit of energy to break down protein and fats and carbohydrates in our food. And then at different life stages worth, we'll take up a fair bit of that energy like during adolescence and pregnancy for women.


And the thermic effect of was only about 10% of energy and say, which is quite significant, but not as not as much as [inaudible]. So energy intake comes from the food and drinks that we have, and then different foods and drinks supply different amounts of energy. So different amounts of calories and pillagers. And this is because they're made up of different proportions of macro nutrients. Anyone had a macro nutrient before? Totally fine. Matt. Very just names big. So they're like our big nutrients. They're the building blocks of food. So all foods can be broken down into carbohydrate, protein, and fat. And certainly foods contain more than others. Like Brad's got a lot of carbohydrate, but not that much fat or protein. Whereas if KC salmon, a lot of protein and healthy fat as well.

So the weight equation is to maintain our body rate. We need to eat how much we expend, all burning each day as a result of our metabolism. So thinking back to that purple bar, how much do we have to exchange? So it's how much our bodies personally need. Weight gain gradually over time reflects a bit of an energy imbalance. So energy intake exceeds how much we need when burning. If what you eat or drink is brighter than what your actual energy needs off the body is very clever, can convert any of those macro nutrients, carbohydrates, protein, fats to say for later on in your talk about why. Sounds so simple, right? For weight loss to occur, we need to recall is an energy deficit. So eat a bit less than my burning each day. So I tip the scales. So we're in a bit of a negative energy dominance and that sort of good old diets. Try to do a little bit of negative energy balance each day. So has anyone ever heard the saying weight loss was 80% diet? 20% exercise?


I guess it's Kinda true because based on that simple science of metabolism, it makes sense to reduce our energy intake as their energy is going to be good by the body to survive regardless of what exercise we do. But with exercise, we only have the capacity to increase our energy expenditure by 20 to 30% so instead of increasing output and we reduce intakes, more things for your body, slight problem or restricting our food or energy intake for weight loss dieting is actually very difficult to stick with and maintain in the long term there. Why is dieting, Calorie, energy restriction just so hard [inaudible].


So what I really want to talk about today is a bit of the science behind what actually happens to your body when you're fasting or dieting. And so fasting is quite severe energy restriction and dieting might just be kind of harming or having a little bit less than your body needs each day. And the hints is it's really hard because your body is actually working against you. So who knows this hungry feeling, feelings of emptiness, gambling, gambling, grounding me feeling quite dizzy. Thanks. Light-Headed. Headaches, irritable, easily agitated. One thing said, and lack of concentration was really difficult to to focus on high level tasks when you don't have enough food. But you're also thinking about food a lot.


We can coin this, the famine reaction. One of my favorite and leading researchers in the field, Dr and under Salice has quite cleverly labeled [inaudible]. There's these hungry feelings. So when we restrict out energy intake like during the diet, and this is the continuous calorie restriction. So we do some a little bit each day when we can't maintain our energy balance. That energy in equals energy out to maintain our body weight. Our body got to love it. Can't distinguish between us wanting to lose some whites and actual starvation and the lasting famine. Is there ever going to be food again? That's how we, yeah, that's how it thinks. So if it thinks it's in feminine accused survival mode and as a consequence, dieting next to very hungry. So our body convert any excess storage from our food into storage. Sorry, into our fat stores in case famine. One day it does come. And if the body thinks that that time has gone, it mounts all these physiological defenses against you to try and stop you losing weight. It wants to hang on to fat stores. And why? Because if you have these stores that are like serious backup, it means you more likely to survive. So this is how our genes think these defenses and to stimulate our appetite and reduce our energy expenditure costs. So if you're not eating as much at things and do something about that.


So unfortunately our body is working against us a little bit and nobody has a number of things, inbuilt defense mechanisms that tend to resist ongoing weight loss or survival. So one of them is to try and keep us at this set point. Has anyone ever heard about a set point in your weight? It's a set body weight and body fat level in particular. It's like a fattest stat like to keep a certain amount of storage. And why is this? We can think about physiology is defending a set point in our weight. So it decides what weight you going to be even for those who are carrying a bit more weight and then actively defense that. So when trying to lose weight, your body works events you because it really doesn't want to lose those stores. And if you do lose the weight, it tries to get me back to where you were again. So CUNY, the way for them, you get hungry. And why? This has no doubt helped us to survive in the past. So there's a bit of a scientific theory called thrifty James. If people didn't have this, they probably wouldn't have survived. So we actually have good genes that are just sort of working against us in this modern day context when there's a lot of food around and no. Has anyone ever experienced a weight loss plateau?


I think most of us would know that when you start a weight loss diet, it's really only effective for a short period of time. This is because our body catches onto what we're trying to do and adapt to this reduced energy intake, the Diet, and we stopped losing weight. So you pick side, let's take a look at some of these defenses and mechanisms. What's it actually doing? The whole swipe loss and he's like even the back of your mind, there is a secret come. Some means coming. It's a combination of Outbrain and I've got, so when we eat less than what everybody needs to maintain that energy balance and it's current, right? It triggers something called the hypothalamus in your brain and your pituitary gland.


These are call nine o centers. When they're triggered, they increase the release of certain neuro chemicals which boost your appetite and trigger hunger in particular on a hormone called Ghrelin. And I liken it to this little, they're down here like a Gremlin that's really crazy and hungry and these hungry hormones are really, really powerful and biologically driving you to want to ate increases hunger, but also preoccupation with food is on your mind all the time. So it takes a lot of effort to actually override these little gremlins and these hungry homelands make it progressively more difficult to keep those in whites. They contribute to those weight loss plateaus and make it really hard to keep sticking to the diet, but also to keep having success. If we're talking about roping kilograms, this means that the longer we die in the hotter and actually to comms to aggressively was white.


I kind of liked this. It's your whole men's and your body fighting. It actually suppresses your chemicals, which normally regulate and reduce your energy intake. So all minds which say, Hey, I'm full, I'm, I suppress the appetite. These include a number of different goal. Nines you don't need to remember them, but if you had to seed them, let them call the sister climbing CCK near a peptide yy and something called GOP one during dieting. The circulating levels of Homer's are quiet low, but they'd normally be higher after eating, so that sends a lot of signals in the body as well.


What also happens is your body reduces and learns the Lectin that we just looked up and thyroid. Has anyone heard how your thyroid kind of can regulate your metabolism? Yeah, so normal to high levels of these hormones circulating, promote an increase in energy expenditure. We've got the energy to go burn and let's do it. I also regulate and keep your metabolism behind or optimal level. That basal metabolic rate is, is at a point where it just can keep going. It's not high, it's not too low, and that increases how much you actually been at breasts.


But in energy restriction when these homeowners with juice, they slowed down your metabolism and how much energy you're burning at rest. So it slows that basal metabolic breakdown and this is a key weight loss. Defence lowering metabolism. Multiple studies have measured metabolism, often having a calorie restriction each day, it can happen within a few hours. So the body's quite good at defending the set point and it does make sense during actual feminine. If found metabolism stayed sky high and we kept burning through energy, we couldn't actually supply the body, we probably wouldn't have survived that long, harsh winter.


Okay, so what actually happens to your body and on a fast is that you've got hormone sending signals to your brain telling you that you're more hungry and that you want to eat more and increases our appetite and that doesn't go away. And our metabolism slowed heart. So it all essentially makes dieting pretty hard. It's called adaptive adaptive thermogenesis. It's actually a scientific phenomenon. And then if you're in a reduced state, if you eat more, you will start to gradually get back to that point. There's another component as well. Energy restriction causes changes, other hormonal changes and in particular there's an increased stress hormones circulating in your system. That's why I think is literally stressful to the body. It's in survival mode. It's thinking, ah, I need to survive. So it is, it is stress calorie restriction, but how long does this effect actually last fall, we know that this famine reaction can literally be reversed within six to 24 hours if you have access to eat to energy balance again, some things, okay. Also I'm tending to worry, I'm going back to normal now and all of the hormonal changes we say with energy restriction go back to normal within a few hours and even after a few weeks of dieting and stuffing and returning to just eating normally. Quite often people might even compensate and eat a little bit more than they normally would, but in that stage, your metabolism, thyroid hormones, appetite hormones, all retention normal within 10 to 14 days.


So this famine reaction practically can reverse within a few hours if you've just been doing it in the short term once you have enough food. Again, the type of my messages, the body is very good at sensing energy and safe, very good at adapting and hanging onto it. Still can intimate fasting. Then because we've been talking about continuous calorie restriction, that small daily restriction can intermittent Austin Sidestep based on pleasant, hungry feelings, feminine reaction, that's yes, it does actually a PA's and have some advantages for appetite control and not feeling quite as hungry. So increased hunger can occur on that continuous daily energy restriction as we've seen with a little days, increases in appetite hormones despite no weight loss. So what that means is conventional dieting has long been known to increase appetite, which you might not even be losing weight because of all those defense mechanisms going on, but intermittent fasting may actually reduce appetite compared to this continuous calorie restriction. Why is that?


Anyone heard occasion genic diets? Yep. That's what you're gonna learn, right? The body and brain prefers to run on that big nutrient carbohydrate because it's it's favorite fuel source. It's really easily and readily bent. So it's very easy for it to metabolize exchange the energy ketogenic diets is the body burning fat instead of carbohydrate. A state called ketosis but only fat from our stores. This ketosis is actually quite hard because it's our backup energy systems and child reserve energy. And technically on starvation probably in the body, as I mentioned, doesn't want to be in because it's quite hard work and stressful for the body to draw on these backups doors and break them down in a way that we can use them as if they were like carbohydrate because the brain likes to run on carbohydrate. So we've got to find a fuel source that the brain will extent, but it doesn't like it.


But severe calorie restriction is saying intermittent fasting can induce this starvation state. And then what happens is when the body's forced to burn fat, your producers something called ketone bodies, so ketosis, ketones, hence ketogenic diet, the production of these ketone bodies, and this is equivalent to the carbohydrate that the brain would run on suppresses appetite after a little while, have you ever been around someone who's maybe been not eating enough and you can kind of smell their breakfast of it? Funky smelling, but it's actually the ketone bodies on their breath and that suppresses appetite and it makes sense that the body catches on that. Okay, food's really not coming. There's no point in being super, super hungry. However, I can actually take up to one to two weeks to induce ketosis through the normal daily calorie restricted dieting, intermittent fasting things to be able to do it.


So a high amount of circulating ketone bodies has been actually measured in into minute fasting and this is objective evidence that intermittent fasting can reduce appetite and induce ketosis. So also thinking back to our whole morons, I mentioned Leptin, a hunger reducing hormone intimate, fostering a case to effect this hormone a bit more differently compared to the continuous calorie restriction during intimate fasting. When you eat normally after fasting day seems to cause Leptin to surge a little bit and it makes sense because eating enough again and according to studies, this third was enough to actually boost your metabolism by about 7% when it had been lowered. So always intimate fasting, perhaps overcoming that lowered metabolism that we see in continued calorie restriction.


So there is a little bit of negative associated with calorie restriction. There are a lot of benefits as we saw in part one, but there is something I think I should talk about. A lot of people who do in Devo on calorie restriction and not be eating enough to make sure that they're getting the nutrients. So you might be at risk of micronutrient deficiencies like iron, B12, zinc. So these are all out little nutrients. So instead of macro, the big nutrients, micro ral, additional nutrients. And we need all of these guys to keep out organs functioning, our immune system strong.


And we know that energy restriction plays with that whole months. It affects the homeowners, which nature regulate and keep. I'll send it on. So when they're done out of balance, it does lead to some less than desirable physiological side effects. So unfortunately the whole model changes, but we say these defense mechanisms, they accelerate lane muscle mass loss as well. Strength and bone loss including bone, mineral density. And what's pretty scary is that this process is accelerated literally two to eight times greater than what we would say naturally aging even in those who aren't that good news is coming. And why does this actually happen? I'm muscles.


Um, muscles, the rest, they've been off a lot of energy so I to keep up, keep out muscle, you have to provide a lot of energy all the time. So the body strips sick because it thinks it's very demanding energy wise and I can't maintain it because I don't have enough energy. So we'll get rid of that first. We won't draw on our fat stores first. And then also if you changes to bone mineral density [inaudible] dear corrosive. So why these are a bit concerning is it can have an adverse effect on muscular Scalia. So that's why people who have been dieting for me is get a burner little density scan, but can intimate bossing second delegate these quite negative side effects. Dieting, energy restriction. Unfortunately no, it doesn't appear to provide any rest slots from these hormone changes because it's quite difficult to overcome the body's natural reactions. We have strong survival but good news. But actually a fee is to be a really sneaky way to overcome our biology, to lose weight, more effective rate, reduce outset points, and keep off the weight and minimize these physiological side effects from restricting energy fasting. So no differences between calorie restriction daily and intermittent fasting. But it is intimate and fasting but not as we know it.

So time and energy balance. These are the two factors that we can modify. What of really exciting research shows. And as I mentioned before, we do know if a person eats to energy balance so that the energy requirements daily 10 to 14 days after dieting, that adaptive response, that famine reaction, which does negatively affect main muscle mass and metabolism and bone health will no longer be apparent even if it's still at a level of body weight off the dieting. So that's 10 to 14 days oftentimes. So perhaps instead of this kind of own off approach in the short term, weekly, a long phone intimate and fostering approach may actually be the secret. So taking more of an interval on off approach to energy restriction. So what am I mean by this? Taking a break from dieting actually gives your body a break, including respite from those hormonal changes that come with icing and the intermittent fasting regimes that we know. It gives it a chance that this makes sense. So what we think is eating to energy balance as many calories as you've burning allows your body to reset after a period of dieting, even having lost body weight. So reset.

So just temporary periods of increased eating during dieting that protects us from muscle loss and musculoskeletal impacts and reduced metabolism. So we see these little surges in Lectin. So let's take a look at the actual research. What does it say? So that was a really landmark study done to illustrate this events. There was a study in overweight and obese men. They went on 16 weeks of energy restriction in one group. They did a continuous energy restriction where they received over the 16 weeks only 70% of what they required for energy balance. So we were closing that energy deficit of about 50% straight for 16 weeks.

Then there was a blown foam intimate group. I've a 30 weeks instead they took an on off intimated approach. So for two weeks they incurred an energy deficit. Same as the other bird in your studying or climates have been sent induction followed by two weeks of energy balance for White Knights in. And so they ate 100% and to me in the intimate of birth. So they did energy restrict and diet for those two weeks. But it was followed by a post diet energy and balance things. So they ate to energy balance but they didn't go through eating absolutely everything and anything and men only intimate diets that long foreman's minutes auditing significantly more. Right. And then on the continuous side, it's like a full kilogram difference, which is quite severe. We know that this greater weight loss in the men and the intimate group wasn't due to increase time on the pipe loss program because it was only an ugly every other two weeks and they actually died and less than the man in the 16 weeks stripe it on the fifth day lights. And in the longterm, the intimate and dieting approach reduced white breaking at six months. So that is quite long term for a study. So they maintained 13 kilograms, so they did gain a little bit back, but they maintain 15 kilograms. Whereas a man who was doing 16 weeks straight regained it all back and fix months was pretty interesting.

So the intimate dining group, they're inducing greater weight loss for the same level of energy restriction but not as often done for shoulder and after time. So it's kind of more bang for your buck in terms of efforts to go to, to lose the weight and the long term weight loss, ninth maintenance. And whoa, I did overcome this muscle loss. It did. We folded in this study, the long form infinite route increased the fat loss and reduced fat gang with [inaudible] thing, my foot muscle mass loss. So that's actually pretty, pretty exciting. So even though the man on the loan form other things, significantly more fat than that on the continuous diet and keeping it off for longer, they were losing no greater amounts of muscle. So of course there's always drawbacks to the study. It was only a small study and I didn't look at the effects on brain health, but certainly promising and he say, what about us ladies?


Yes, we've saved yourself in your mind to a shorter term study was conducted me, I'd go right. And then over six weeks there was a continuous energy restricted group that reduced their energy intake for the entire time for the, so for the entire six weeks. Then there was an intimate group and they did a slightly different approach. They dieted or reduce their energy intake for about 11 days, followed by three days where they could just be to energy balance and they repeated that three times. The intimate group lost more weight after the six weeks compared to the continuous group. Also liking men that had changed greater fat loss but didn't play significant amounts of muscle. What's really exciting is they mentioned metabolism in this study and the women in the long form in some in that group maintain a higher metabolic rate compared to the continuous group because they have already caught on to what they were doing and reintroduced that metabolism.


So like this suggest that this long form a long term approach and intimate and a fasting versus I'll strike conventional calorie restriction for a certain number of waves and so long as you can tolerate it, it might actually prevent a lower metabolic rate and it could be to do with those little Lipton surges when you get access to aiding to energy pounds because lectins regulating metabolism. So this approach also seems to sidestep a lot of those hormone changes. Then also gripes sort of could be that taking a break from dieting, potentially his little metabolic boost and jumps stuff that allows dieting


Well, so psychologically I feel like that there are some benefits knowing you have periods of rate fading to energy balance. My use, the feelings of being sort of I believe restricted and deprived all the time, it can actually make sticking to it more motivating and successful. Think about a 12 week side ahead of you. My breaks, you have to eat less, you're going to be hungry. Things pretty daunting if not impossible, Ryan all encompassing. It's also easy to throw in the towel and give up. But what if he actually has something to look forward to where you can actually be what you wanted?


The long form intimate fasting. You might also be a way as sidestepping a lot of the negative psychological side effects that I particularly say like shame and guilt associated with I fed the Diet. It was made on the Diet actually. Got It. But you can also still eat out. So actually with this approach and if you have any on plan of eating or deviations from the Diet, and that's assumption, that's a lot more realistic. So I think move over these all or nothing approaches, it's a longer form that's imminent. Costing approach is definitely a viable alternative to challenge traditional continuous dieting and even these intimate fasting regimes that we're saying now. So intimate fasting does seem to be the secret, but you notice we know it in popular culture.


So I really hold that in mind. What do I recommend? Take a break from Dyson. You're trying to lose weight. It abuse. Spending some time in this period of complete energy balance yields better hormonal weight loss and body composition responses. So maintained in muscle mass energy restriction. So even if you wanted to still do an intermittent fasting approach, like the five to give your body a break after a few weeks, do it on off, then just let your body reset. So I definitely like to look at this long form intermittent fasting regime and I've done it with a few clients and practice, have a few weights of dieting, for example, two weeks where you're causing and note energy deficit followed by two weeks of just eating to into balance. And so what the research is showing is up 30% might be that kind of sweet spot of how much to reduce by, which would in theory results in about a Cuellar weight loss.


So this can help to bring your body down in terms of that set point and keep the body normal lives. So instead of a big slippery dim, I think about the plateaus, it's like taking little steps, sit down or chill out, take another step. So just bringing it down and maintaining it. So a dietician like me can determine what your unique energy requirements are based on the physical activity, any medical conditions that you might have, and actually translate this to what meals and sex could look like for you. Energy restrictive wakes and you know who waves what, what does it look per day of Energy Balance Look like? Because also with Ketosis, we know that carbohydrate and fat seem to play a role in kicking the body into more of a summation state. We can also play with your intake of carbohydrate, protein, and fat ratios. And this can also be important for training. So say if you're wanting to exercise event, you can still follow this approach and making sure that you get enough carbohydrate and protein for your, your exercise training requirements, while making sure that you're not risking any of those nutrient deficiencies. But I mentioned they're literally micronutrients.