Podcast Episode 41 Transcript – Choosing the Right Sized Calorie Deficit and Rate of Weight Loss

Leah Higl

Welcome to the Ideal Nutrition podcast. I’m Leah Higl and I am here with my co-host Aidan Muir.

Last week we discussed all things calorie surpluses, so it only makes sense for us to go in the complete opposite direction this week and talk about calorie deficits. So I actually want to start with briefly talking about how energy [00:00:30] balance works and what a calorie deficit actually is because I think it adds a good kind of background to what we’re going to talk about. So energy balance is basically the balance of calories coming in versus the calories being burnt through metabolism and daily activities.

So a calorie deficit specifically is when you are burning more calories than what is coming in through food, so what happens in this case is your body still needs to make up for that energy, those calories, somewhere. So [00:01:00] what it’s going to do is go to your internal stores, so things like your muscle mass and body fat and take the calories from there, hence why you lose weight when you’re in a calorie deficit.

But before we get into exactly what size calorie deficit you should use, we want to cover one important and common question and that is, is it possible to actually be so low calorie that it prevents weight loss from occurring?

Aidan Muir

The short answer is no, [00:01:30] but it is much more complicated than that, obviously. I’ll start off with one thing that’s kind of unrelated to that, but then work backwards to what we’re going towards. So a lot of people will be like, “Calories in versus calories out is outdated thinking.” Or they might say it’s not calories, it’s hormones or add a lot of other reasons why it’s not calories. But calories in, calories out works because the body is made up of calories. As you said, [00:02:00] one kilo of body fat is made up of about 7,000 calories. It’s not exact science, it depends on how much water is in that adipose tissue and all those kind of things, but it’s close enough. It’s pretty much roughly that on average.

And the hormones and stuff like that play a role in our energy expenditure. It’s a moving target. Maintenance calories is a moving target. The amount of calories you require to create calorie deficit is a moving target. Things like lower thyroid hormones, reduce your energy [00:02:30] expenditure, higher [inaudible 00:02:32] makes you hungry and you probably eat more calories. Hormones are factored into the calories in, calories out kind of model.

So let’s say you burn a certain amount, as a factual statement, and you eat less than you burn. Where is that deficit made up of? Where does it come from? Because we can’t just create energy out of nowhere and it can’t just disappear or anything like that. If we’ve burned a certain amount as a factual statement and we’ve eaten less than that, it has to come from our internal stores because we only get it externally from [00:03:00] food.

That’s why a calorie deficit works. It’s going to come from our body fat, could come from our muscle that’s also a storage form of energy, but that’s why a calorie deficit has to equal weight loss. There’s a lot of people who say stuff like, “I’m in a calorie deficit, but I’m not losing weight.” But the definition of a calorie deficit involves weight loss because of this mathematics I just went through there.

So now getting into that question of like, “Can you be so low calorie that it prevents weight loss?” Literally this thing about [00:03:30] the mechanism I talked about, say you’ve burned a certain amount, you’ve eaten less than an amount, that leads to weight loss. How is it possible for it to be a situation where you’re eating very low calories and you’re not losing weight? The only way that that is physically possible is if there are adaptations occurring that bring your calorie expansion down to the point that you’re eating at, and that comes from a grain of truth. That’s why people talk about things like starvation mode and stuff like that. I don’t like the term starvation mode. It’s not a thing. But metabolic adaptation is a thing which [00:04:00] we have talked about previously, but your body can adapt in certain ways. It can reduce energy expenditure through certain means.

It can only take it so far though. And there are some cases in the research where people are on low calories and they’re also not losing weight. One example of this is when females are in a state of low energy availability, doing heaps of exercise, they’re on relatively low calories, they have evidence of being on low calories due to they’ve lost their period and stuff like that. That’s a sign of adaptation. That’s a sign that they have been [00:04:30] in a state of low energy availability and they happen to be eating the exact same sweet spot where they’re eating as many calories as they’re burning, even though they’re not eating many calories. But even in that kind of rare situation which is one exception to this, if they eat less than that, they still lose weight. So that’s why the short answer is no. It doesn’t prevent weight loss. It’s never a question of am I eating too many calories or too few? It’s always too many calories. That doesn’t make it a good idea-

Leah Higl

Yeah, if you are on a really small amount of calories and you’re not losing weight, that’s probably a sign that there’s some other things going on that might need to be addressed.

Aidan Muir

Yeah, for sure. Exactly. I’m really cautious when I have this conversation because, and it’s easier for me to have it over a podcast than it is face to face with a client, but it’s a really cautious conversation because people hear me say that and be like, “Oh, Aidan’s just saying eat less calories always.” I’m like, “That’s not what I’m saying.”

Leah Higl

That’s [00:05:30] not the takeaway.

Aidan Muir

I’m just answering a question is it possible to be on so low calories that it prevents weight loss? And that’s never the issue. Every time a study has been done in a controlled environment where they’ve put people on low calories, they drop weight like crazy. The lower calorie you go, the quicker you lose weight. In the real world where there’s other variables, it happens quite a lot. People talk about this. But there’s a lot of variables that go into this. One is as we’ve spoken about previously, [00:06:00] but underreporting.

It is huge. There is one study that I always reference where people underreported by an average of 47% in terms of what they thought they ate yesterday and somebody in that study was 80% under in that they were recorded to have eaten over 3000 calories but what they said was 800. That doesn’t make people liars, but it does mean we struggle to communicate what we do and in that study, the most [00:06:30] important statistic that I take away from it is nobody got within 20%. Which therefore means if somebody’s reporting low calories and we’re not even adding 20% onto it, knowing this kind of data exists in the research, we’re probably missing things because the example I would use personally is… I don’t know, I probably eat a slice of cake once every two months, but if somebody asked me what I eat…

Leah Higl

You wouldn’t factor that in.

Aidan Muir

I wouldn’t factor that in. But that still calories. Stuff just goes missing. Yeah.

Leah Higl

Yeah and I find even when people [00:07:00] are tracking calories, whatever they do consistently day to day is what they’ll factor in but they might do something a little different every single day that adds calories but they’re not going to think of that as one of their fundamental habits. But it is calories coming in at the end of the day and I think that’s why underreporting can be quite large.

Aidan Muir

Yeah, for sure. And I suppose this is not what we really wanted to be talking about, too [crosstalk 00:07:23].

Leah Higl

Yeah, we kind of took a little bit of a side turn, yeah.

Aidan Muir

Yeah. The last thing I was going to touch on is how do medical conditions factor into this? Because a lot of people are [00:07:30] like, “Oh, calories in calories out falls apart with medical conditions.” It still doesn’t. It still doesn’t. Those are factored in. For example, somebody with hypothyroidism. Their energy expenditure is reduced. Maybe it’s by roughly 15%. It’s hard to actually get numbers on this. I actually looked quite hard because I was writing an article on this and it seemed like 15% reduction if it’s not addressed and that varies based on how low their thyroid hormones and everything like that gets.

But once again, that’s still in the model. It’s just that it’s harder to lose weight, obviously. It’s harder to create a [00:08:00] calorie deficit. I’ve got heaps of empathy for that. But that’s still part of the model. PCOS we’ve talked about, we’ve talked about maybe basal metabolic rate is reduced by 14 to 40%. It’s potential that that exists. But that’s once again, factored into the model. It’s not weight loss is impossible. It’s still the calories in, calories out model. It just adjusted based on these different situations.

Leah Higl

And for some people that if you’re not sure whether you fall into the camp of, “Oh, maybe I’m under reporting or maybe [00:08:30] for whatever reason have a really low basal metabolic rate,” you can get your RMR or your BMR tested, so if you think that’s a problem for you, go do it. Why not? See what the actual kind of underlying cause is for you to be on low calories and continue to not lose weight.

Aidan Muir

Yeah. I’ve had some outlier clients from that. I’ve been surprised as well. Some people who are significantly different to what was predicted basically, so it is worth looking at for sure.

Leah Higl

And not that expensive. I’ve recently looked into it. I think it’s only $100 or something, so [crosstalk 00:09:01].

Aidan Muir

[00:09:00] Yeah and if this is a major source of frustration, $100 is probably worth it, yeah.

Leah Higl

Trial it. But going back onto more of what we were talking about today, is let’s get into the pros and cons of having a larger calorie deficit versus a smaller calorie deficit.

So let’s start with larger deficits. So this is talking less than 70 to 75% of your maintenance calories, so anything more aggressive than that. The first thing that always comes up for [00:09:30] me is definitely hunger. Hunger is a huge one when it comes to barriers to success with weight loss. It’s a very uncomfortable feeling and the larger the deficit, usually the quicker that hunger is and more severe it comes on.

Secondary to that, you’ve got just the level of restriction that you need to have when you’re on a very large calorie deficit. You’re less likely to be able to go out with friends, enjoy an extra slice of cake on your birthday or you can’t [00:10:00] really do those things when your calorie budget is so low. And then kind of rattling a few things off, you’ve got fatigue so if you’ve got way less energy coming in, you’re going to be tired. Muscle loss, so potentially not a great thing for athletes where muscle retention is important, possibly not a great thing for them to do in the long term. Same with kind of training outcomes, so training’s not going to feel as good. Potential disruptions to sleep is another one [00:10:30] as well as increased risk of injury if you’re training, as well as illness.

And then kind of the final part is potential issues with the relationship with food. So I don’t know if there’s many studies on this looking at people’s relationships with food when they’re in a large calorie deficit, but just talking anecdotally and through the clients that I see, most people struggle with a really large calorie deficit and kind of develop a bit of a warped [00:11:00] view of food and their relationship with food potentially not the best after that. Binge eating is one that I think can come from [crosstalk 00:11:11] that really, really severe dieting.

Aidan Muir

Yeah, yeah. It is one of those ones where research does exist on that topic, but I don’t think we need research. We see this so much.

Leah Higl

I’d love to kind of be able to throw out stats, but it’s one of those things where I see it in practice so much and I know it’s a real thing.

Aidan Muir

Yeah, yeah, yeah. So from [00:11:30] a positive perspective, why would someone want to do that?

Leah Higl

It’s quicker. I always talk about when I’m talking high clients, for me, I love aggressive dieting. I like to drop the weight quickly. So even though I’m an athlete, technically, I’m a power lifter and it would be best for me to do it slowly, there’s nothing that motivates me more than seeing that scale go down as quickly as possible. So I think at the end of the day, that’s probably the biggest driving factor for [00:12:00] why someone would choose a large calorie deficit. It means you’re spending just less time in that deficit. Get in, get it done, get out. So that’s a good aspect of it.

Aidan Muir

Yeah, for sure. And that’s also another thing from the sustainability perspective where if you go twice as quick, you’re in there half as long and if even a moderate calorie deficit is a burden for you and you might have to, not miss social occasions, but you might have to hold back at social occasions or [00:12:30] whatever it is, you just spend a shorter period of time like that. And I often view it being not only is it a shorter period of time, it means you have more time on higher calories where you have more flexibility.

So I actually don’t really have too much bias in either direction because we’ve just rattled off a list of 10 plus things as to the [crosstalk 00:12:51] downsides of it’s and there’s only one good side but the one good side is actually pretty valid because it also means you have less time experiencing those 10 plus downsides as well.

Leah Higl

Yeah. Where [00:13:00] the restriction is minimal or severe, I feel it’s the same [crosstalk 00:13:06] so in a way almost, I’d rather go through a period of time that’s smaller, where I’m more uncomfortable, than go through minimal kind of restriction for a really long period of time. But everybody’s different and that’s why this really comes down to personal preference.

Aidan Muir

Yeah. So from an athlete perspective, one of the biggest things that I’ve always cared about is obviously just body [00:13:30] composition, trying not to lose muscle while in a deficit. Potentially gain it if you can, but trying to minimize muscle loss and coming from that background of me reading on bodybuilding.com and stuff like that, people often talked about if you drop weight really quickly, you’re going to lose a lot of muscle and that has been challenged a little bit, that idea. Are people saying that without actually looking at the research?

But I do want to go over some interesting research on the topic and that phenomenon that people are referring to [00:14:00] does exist, but it’s a nuanced topic because then you’ve also got to factor in the time. So the first study I’m going to talk about is titled effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. And they basically did 0.7% weight loss per week, which is theoretically a 20% calorie deficit, versus 1.4% predictive weight loss per week, which they did was a 30% calorie deficit. The maths doesn’t fully check out for me, but [00:14:30] either way they were comparing slow versus fast weight loss and they had 24 athletes split over two groups and they were lifting four times per week, which is pretty relevant from the types of people we work with.

So the fast group… Oh, sorry. I was going to say so both groups actually had similar total weight loss at the end of it. They both lost 5.5 kilos, but the fast group got there quicker. It got there in around five weeks, whereas the slow group got there in about 8.5 weeks. So, I don’t know, slow 8.5 weeks to [00:15:00] lose 5.5 kilos. It’s not overly slow. It’s just slower than the alternative, whereas the other group lost just over a kilo per week. So the slower group gained 2.1% lean mass. They gained muscle while losing 5.5 kilos over 8.5 weeks. That’s a pretty impressive outcome.

Leah Higl

Oh, and this is an elite athlete, so this isn’t even gen pop.

Aidan Muir

Yeah, it’s a pretty impressive outcome. And the fast group had their lean mass remained unchanged. So they lost over a kilo [00:15:30] per week without losing any lean mass. So both groups actually got pretty impressive outcomes, but it kind of supports both arguments in a way where it’s kind of like do it a little bit slower, you’re going to preserve more lean mass or gain more lean mass. Do it faster, you get it done quicker, but it’s not like you’re dropping lean mass like crazy, particularly in this case if the training’s good, protein’s good, you’ve got potential to gain or maintain muscle. So that’s a bit of an interesting one.

Leah Higl

Yeah. So perhaps the downside of [00:16:00] dieting really aggressively in terms of muscle loss may be not as huge of a deal as some people make it out to be.

Aidan Muir

Yeah, for sure. The second study I was going to talk about is moderate energy restriction with higher protein diets results in healthier outcomes in women. And they basically compared 0.5 kilos versus one kilo per week for four weeks. They were not all elite athletes, but they were lifting weights regularly and they had 1.4 grams per kilogram of body weight protein per day or more. Basically [00:16:30] at the end of the study, there was no change in lean mass for either group, so theoretically the group that dropped twice as quick still had the same outcomes from muscle mass. The quicker group had their testosterone drop by 30%, but this was also in women. Do they really care about it that much? I don’t know.

And the performance results were interesting in that the 0.5 kilo group had no change in performance, whereas the faster group had their bench press go down a little bit, but their ability to squat 50% of their body weight to failure improved. [00:17:00] So their actual squat with lighter weights improved more than the group that lost quicker than the bench press. I don’t know, it was pretty random basically, from what I could see.

Leah Higl

Yeah, actually it’s like a little bit of an outlier, maybe.

Aidan Muir

I think so, yeah.

Leah Higl

Yeah, but still, it kind of goes to show that you’re not necessarily going to get weaker just because you’re dieting more aggressively.

Aidan Muir

Yeah. Exactly, yeah. And the whole point of those two studies I was really talking about is just because I am a believer that does actually… If you’re trying to preserve as much lean mass as possible, you do want to be going [00:17:30] slower. But it’s just not as bad as some people would make out if you do go quicker and another thing is that probably the more body fat you have at the start, the easier it is to go quicker without losing muscle. The leaner you get, the harder it gets.

Leah Higl

Yeah and I think there’s a difference in the severity of diets, too. Even if we’re talking aggressive, we have everything from 500 calorie diets to some people losing just a kilo per week would be deemed aggressive. So there’s a huge kind of, I guess, [00:18:00] room to play within that. Where if, yeah, if I was on a 500 calorie diet, that would be a huge deficit and there’d probably be more of a chance of muscle loss but something like a kilo per week, maybe not a big deal.

So based on the logic of the leaner you get, potentially the more at risk you are of muscle loss with a larger calorie deficit, we have this kind of one paper from Eric Helms that’s titled evidence based recommendations for natural body building contest [00:18:30] preparation. So obviously looking at people that are quite muscular, that are looking to get very lean. So the study proposed that about a 0.5 to 1% weight loss throughout a body building prep with the higher end being utilized at the start and the lower nearer to the competition is probably what is going to be beneficial and if you go much more than that, perhaps there is a chance that you will lose lean mass, kind of the leaner that you [00:19:00] are.

Aidan Muir

Yeah. And that’s the study I’ve referenced so, so many times because there’s so many opinions in, say, bodybuilding, how to get super lean and stuff like that and that paper seemed to be the first one to really just put it all together. It was also one of the ones that first proposed higher protein targets than the recommended amount. Previously people have talked about 1.6 to 2.2 grams per kilogram body weight per day for optimizing muscle growth, but nobody had ever been like, “What do we do with people who are sub 10% body fat looking [00:19:30] to get at leaner and maximize muscle retention?”

Leah Higl

It’s just such an outlier.

Aidan Muir

It’s such an outlier. So there was not a lot of research on body building, but he summarized it at that time and there’s been more research since then, but it’s almost really, really relevant. And under those circumstances, like 0.5 to 1%, it makes a lot of sense. And another complication, this is going to be a niche area, not relevant for a lot people, but what if you get near that 5% as a male kind of body building?

Once you’re around that 5% mark, you don’t want to go overly slow, [00:20:00] even if you’re risking muscle loss, because you don’t want to be that lean for too long. So you’re not only balancing, “Okay, I’ve got to go relatively slow to minimize muscle loss.” You also don’t want to be like, “I don’t want to turn a 16 to 20 week prep into a 30 week prep and go super, super slow.” Because we know there are also downsides of being super, super lean.

One, the relationship with food thing, the obsession with food, but then also markers like your thyroid function and testosterone. Thyroid function actually gets quite suppressed to the point that some people are classified as [00:20:30] hypothyroid because they’re that lean. You don’t want to be there for longer than necessary but I do like that idea of 1% at the start down to 0.5% at the end, because a lot of people will start their preps at, I don’t know, 15% body fat, 15 to 20% body fat. But that also makes it interesting because people who aren’t bodybuilders are often starting their fat loss phases around there too.

Leah Higl

Yeah, 100%. And just thinking about what happens practically with weight [00:21:00] loss is most people start more aggressively and as they lose weight naturally kind of just go into a smaller calorie deficit and they lose a little bit smaller percentage per week, per month or whatever. So that usually is what people mostly do when they’re having kind of a successful weight loss bout.

Aidan Muir

Yeah. And I guess the conclusion that we’ll go with is I think it’s pretty open to individual choice. I personally do like that range I talked about, 0.5 to 1% or even [00:21:30] putting numbers in, like half kilo to one kilo per week and stuff like that. For a lot of people, some people would like slower than that. Other people would like quicker. And I think the key is being open minded to different approaches.

Something that I found interesting quite recently, there’s two people, Martin McDonald and Eugene Teo, both of them have massive followings on Instagram, both of them know heaps about nutrition, both of them, to the best of my knowledge, have good relationships with food and stuff like that and both of them recently did rapid fat loss phases. [00:22:00] And for them, they’re just like, “This is my preference. I know the risks associated with it, I know the downsides, I know all of those kind of things and I know the upsides of the fact that it’s quicker and I’d prefer to do it quicker.” And they did that and they showed it in a really interesting way and they’ve done podcast content, they’ve done YouTube content and all those kind of things. And it’s kind of like if you weren’t open-minded to that kind of stuff, you’d think that’s the dumbest thing ever.

Leah Higl

This is true. Yeah. But I really resonate with that approach. It’s not something I’m going to go and use with a bunch of clients because I know the risks, [00:22:30] but I know myself enough to be using an approach like that for me.

Aidan Muir

Yeah, for sure. So it’s an interesting idea to just be open-minded to it and think about, but I do like that kind of thing in terms of that more moderate as well, I suppose you could call it. But as you can tell from the pros and cons list, there is a lot of downsides, but the upside of it being quicker could outweigh that for some people.

So this has been episode 41 of the Ideal Nutrition podcast. As always, if you haven’t already and if you have access to being able [00:23:00] to do it, if you could please leave a rating and review, that would be greatly appreciated.