How Fat Loss Works

This week we are explaining how fat loss actually works. We are going beyond the simple “burning calories” and instead look at what is physically happening to a fat cell, where the energy goes, what happens to your metabolism, and why the scale can behave so differently from actual fat loss.

If you have questions, or topics that you want to hear about, head over to our Instagrams https://www.instagram.com/bayleethedietitian/ or https://www.instagram.com/brianna.dietitian/ and send us a DM! You can also follow the podcast https://www.instagram.com/mocktailminutes/

Featured Mocktails: 

Bloom Pop

Ultima

Click play, sip back, and be empowered.

Transcript

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Baylee 0:21

Hello, everyone. Welcome back to this week's episode of Mocktail Minutes. This is Bailey

Brianna 0:26

And this is Brianna

Baylee 0:28

This week I'm drinking a Bloom Pop. So I hosted a girls' night out with a trainer that's in my area, and they sent these for our event, and it's the Rocket Blast flavor, which apparently is very hard to find. It is delicious. It's like a prebiotic soda.

Brianna 0:44

like a Bomb Pop flavor Oh

Baylee 0:47

But it's really good. Two grams of added sugar, sweetened with stevia. like it

Brianna 0:52

I just had my Ultima today. Grape.

Baylee 0:55

OG and the grape.

Brianna 0:56

I just, I go back and between raspberry lemonade and the grape

Baylee 1:01

Yeah. Josh is feeling crazy. He wants to do cherry pomegranate. He always does pink lemonade. He's like, "I need something different." So I gotta order new

Brianna 1:10

space and all that, you

Baylee 1:11

going wild. This week, we are talking about how fat loss works. I... So this is kinda ex- inspired. I saw a, I don't know, TikTok or an Instagram post, someone explaining this. I was like, that's really interesting," because I think when we think about fat loss, it's like, where is the fat going? What's actually happening?

Brianna 1:33

Yeah

Baylee 1:34

and it's not something I always think about all the time. Yeah, I know the process, but we just we don't talk about it in sessions. We don't talk about it with people. So we thought this would be a fun topic to go over. What is actually happening when you lose fat instead of just thinking about it as burning calories, but looking at it as what's physically happening to a fat cell? Where the energy goes, what happens to your metabolism, and why the scale can behave so different from actual fat loss. So that's what we're gonna dive into today

Brianna 2:08

Yeah. So at its like most basic level, your body needs more energy than it's getting from food over time. So maybe like you're eating less, so you have a deficit or you've increased your activity to more than you're used to. So it needs, it's not getting as much as it needs and it has to pull stored energy from somewhere and body fat is one of those stored energy sources. But it's a lot more complicated than just like calories in, calories out. It's not like, "Oh, I ate 400 calories less, so now I'm gonna, you know, break 400 calories out of my body fat and use it." Does that make sense?

Baylee 2:50

Yeah, so your body's just it's going to constantly adjust what kind of fuel is using it. So you're always going to be burning a mixture of fat, carbs, some protein, stored glycogen, and other substrates. And so when energy coming in isn't enough to cover that energy being used, your body has to basically mobilize stored energy.

Brianna 3:14

Угу

Baylee 3:16

fat tissue

Brianna 3:17

Yeah. And your, your fat cells don't disappear, so they just...

Baylee 3:24

always interesting to

Brianna 3:25

Yeah

Baylee 3:26

you're not losing fat cells.

Brianna 3:28

Mm-mm. No, they're just, they're, they're just shrinking. So like they're there because if you think about it, fat is a, it's storage. Like it's a, we use fat, we store it as energy. So your body, that is a machine that needs to have energy, you know, on standby, it needs places to store it. It stores it in other places, but also like your fat cells. So they don't completely disappear. They're still there, they just shrink. So, you know, fat storage increases, the cells get larger. When you're in a deficit or you're pulling from that stored fat, fat is released and the cells get smaller, but they're always still there

Baylee 4:08

And your body can make more fat cells in

Brianna 4:11

Which is, yeah. Which is usually what's happening when you are, like severely overweight. It's like you've kind of maxed out the fat cells that are, that you already have, and now you're creating new ones. This is what we really don't want. But yeah, you never lose your fat cells

Baylee 4:30

Which is why it's easier almost to gain the weight back. 'Cause yeah, you don't really lose them, we can make more. when we think about our glucose, like your glucose is gonna go to your muscle and your liver. There's only like a limited amount of space for that. So once your liver and your muscles are full, it's gonna start going to your fat cells. Unlimited storage here. And then there's like a whole set point weight theory type thing which we won't get into today, which is why you don't just like simply explode, but you can continue to make more fat cells. So your body has to get the fat out of the fat cell. This is where the actual fat loss process begins. stored body fat is stored as triglycerides inside of your adipocytes, which are your fat cells. A triglyceride is three fatty acids with one glycerol molecule. So when your body needs stored energy, Basically, you're breaking those triglycerides apart, so then they're broken down into fatty acids and glycerol. The fatty acids then can leave the fat cell and enter your circulation

Brianna 5:39

Use it for, you know, energy. And another, a, a big s- a big part of whether or not we are breaking fat out of the cells is, like, hormones. So hormones help determine whether or not you're storing fat or releasing fat, so they're always-- your cells are always getting signals, and hormones is a way that it, it signals for your cells to do a certain action. So they're either getting signaling that's like store energy or release energy, and a lot of hormones play a part in this. I think the biggest one that we talk about in terms of weight loss, especially, like, because we focus a lot on, like, blood sugar management, which is why we focus on blood sugar management, is insulin. So insulin in particular is like a storage hor- hormone. So after eating and your glu- your glucose rises, insulin gets released, and your body, body shifts towards energy storage and away from releasing stored fat. So if you are taking in energy, your body is not going to break energy out of its cell to use it. It has energy now that needs to be stored. This doesn't mean that insulin necessarily makes you gain fat or only stores fat. It does, but it also stores a lot of other things. Like, it's, it plays a role in building up muscle as well. But if you are constantly having that signal of s- fat storage being floating around all day in excess amounts, it'll, is a little bit harder to utilize your stored energy as an energy source because your body is gonna be wanting to focus on storing more energy for later. This doesn't mean that you can't lose fat while having insulin resistance or having high insulin, but it does make it harder. So it's one of the signals that, you know, signals fat storage, fat mobilization, or fuel selection, but you also have, like, epinephrine and norepinephrine doing this, glucagon, growth hormone, cortisol, and then other things like your energy availability, exercise, and then your nervous system. So the important thing is the net balance over time

Baylee 7:42

Yeah. So then, like, when we're thinking about releasing fat from your fat cells, this does not mean you're automatically l- losing body fat.

Brianna 7:51

Ja

Baylee 7:51

body can release fatty acids and then just put them right back into storage. There are two processes that happen. You have fat mobilization, so fatty acids leave your fat cell, fat oxidation or fat storage. So those fatty acids are either used or stored again. For an actual loss to occur, fat oxidation needs to happen more than fat storage over time. And so when we think about this if we look at fat oxidation, the fatty acids can be transported into cells and eventually into your mitochondria. The mitochondria are where a lot of your energy is produced. Powerhouse of the cell.

Brianna 8:32

Jeg har også det samme.

Baylee 8:33

undergo beta oxidation.

Brianna 8:35

Угу

Baylee 8:36

this breaks the fatty acid down into smaller units that then enter what's called a citric acid cycle. These are fun things we get to talk about in dietician school

Brianna 8:46

Literally. The things that make you lose sleep, it's this right here

Baylee 8:50

acid cycle. so we're trying to simplify it as much as possible by j- I think it's interesting to share. But once they're in that cycle, electrons are then transferred through an electron transport chain, basically allowing your cells to produce ATP, which is a usable cellular form of energy. So very simplified, we have a stored triglyceride, goes to fatty acids, goes to your bloodstream, goes to your muscle and tissue, your mitochondria, goes to your beta oxidation, your citric acid cycle, the electro- electra- transport chain.

Brianna 9:26

Say that three times fast

Baylee 9:27

yeah, and then energy is used by your cells.

Brianna 9:30

Угу

Baylee 9:32

actually goes

Brianna 9:33

Yeah. And I think this is why it's- people make it really simple, like, you know, train fasted 'cause you, you use fat, and like all this. Like, just because you're using fat as an energy source when you're training does not mean you're losing body fat because this is all happening. So you have to have a lot of beta oxidation going on over time to lose the fat. But this is where you're f- the most of it is going. And so, you know, a lot of people say like, "Oh, where does the fat go?" And like, "Oh, you sweat it out or you poop it out." And I mean, those aren't incorrect, but it's not like the primary pathway. Like, the primary pathway is like these fatty ac- acids are getting oxidized. Their carbon atoms ultimately become CO2, so you're like breathing them out, you know? And then the hydrogen becomes part of H2- H2O, so water. So when you've metabolized stored fat, it ultimately leaves your body through your lungs by carbon dioxide and your kidneys, skin, and lungs through water. So this is why you literally breathe out a significant portion of the mass of oxidized fat. This is also why, like, you breathe heavy when you're working out. Like, yes, obviously you need to take in more oxygen, but that's also 'cause you're building up a lot of CO2 that you need to breathe out. So, you know,

Baylee 10:52

You

Brianna 10:53

it's gonna

Baylee 10:53

out your fat

Brianna 10:54

just breathe it out, you know? Just breathe out the fat

Baylee 10:56

Two. I guess to clarify, you're not breathing out literal fat.

Brianna 11:01

Yeah

Baylee 11:02

exhaling the carbon atoms that originally made up the fat molecule. So

Brianna 11:07

Mm-hmm.

Baylee 11:07

yeah, you can breathe out fat,

Brianna 11:09

It's also like why, 'cause sometimes people will be like, "Oh yeah, sweat. Like sweat and pee." Like, you- just because you're peeing a lot or sweating a lot also doesn't mean you're getting rid of like the substrates of oxidizing fat. Like getting in a sauna, you're not losing fat because you, your body didn't need to go through beta oxidation To sit in a sauna

Baylee 11:29

like, when we look at weight loss your body isn't only burning fat. During a calorie deficit, your body doesn't just be like, "Oh, we're only gonna look at fat."

Brianna 11:37

Угу

Baylee 11:39

carbohydrates, fat, protein. The por- the proportions change depending on how much you're eating, what you're eating, your exercise, your intensity, your glycogen availability, your hormones, your training status, your body composition, the duration of your deficit. This is exactly why weight loss is not the same as fat loss because you can lose glycogen, water, muscle tissue all at different rates. And so I think that's a great point is, like, when people do this on, they're like, "Oh, nice. The scale's down." It's not because you just want... it's not because you just lost three pounds of fat. You're not gonna do that. That's not how it works

Brianna 12:19

No. And that is a b- big common misconception on why we're so like, don't always focus on the scale because it's not telling you the whole thing. So like, yeah, maybe at first you lose like a quick 5 to 10 pounds relatively quickly. It doesn't mean 5 to 10 pounds of fat, like you were saying. It's usually like your glycogen has decreased. You know, like your liv- liver and your muscle stores carbohydrates as glycogen. Those have decreased. When glycogen r- decreases, water decreases because, what is it, like four little units of water for every Glycogen or whatever. You're getting rid of that, you're getting rid of water. So you're also gonna have less food in your digestive tract, changes in your sodium, changes in inflammation, like fluid balance. That is really what's happening in the beginning when you see those rapid 5 to 10 pound different on the scale, not fat. The scale can stop moving when you're trying to lose weight, but it doesn't mean you're not losing fat. Yeah

Baylee 13:15

So yeah, like you could be down half a pound in fat, but up a half pound of water.

Brianna 13:21

Mhm.

Baylee 13:22

on the scale change,

Brianna 13:23

Mm-mm.

Baylee 13:24

it could be happen due to what part of your cycle are you in. Did you have more sodium? Did you have more carbs? Did you have a hard day of lifting? Is there some inflammation going on? Did you sleep poorly? Are you constipated? Are you traveling? Are you having alcohol? Changes in hydration. is why we look at trends. It's gonna be more useful than like I weighed in once this month. We wanna look at what your body is doing over time because one thing to think about, too, with a deficit, your body can start to adapt. This is where like our previous episodes about like metabolic adaptations, we've talked a lot about this. Your body doesn't love an extended deficit. As your body weight decreases, your energy requirements also decrease. A smaller body requires less energy. But body can also make changes to adapt with energy expenditure. So you may unconsciously move less, fidget less, sit more, take fewer steps, have less just like spontaneous neat movement. Overall, this can often happen when our bodies start to adapt due to intake for too long a time

Brianna 14:33

So the whole process is, this is the process. Calorie deficit, and we wrote it down 'cause this is a long one. Calorie deficit, energy availability decreases, hormone and cellular signaling shifts, lipolysis increases, triglycerides turn into fatty acids and glycerol. Fatty acids enter circulation. Some are restored. You're not-- Some parts of that goes right back into being stored. Some are transported into tissues. Fatty acid enters mit- mitochondria. Beta oxidation happens. You go through that citric acid cycle that I have nightmares about. You create ATP and heat. Carbon turns into CO2 that you breathe it out. Hydrogen goes to H2O that you lose through water, and then fat cells get smaller, all while your body weight is decreasing, energy expenditure decreases, hunger signals increase because if you are losing weight, you're meant to survive, you're gonna feel hungrier. NEAT may decrease. This is where your NEAT movement goes down, metabolic ap- adaptation occurs, calorie deficit becomes smaller because your NEAT movement has decreases, and fat loss slows. So the takeaway is fat loss isn't simply eat less, then you burn fat, and then you lose weight. It's more accurately

Baylee 15:44

definitely need to create more of a sustained deficit,

Brianna 15:48

Mhm.

Baylee 15:49

your triglycerides. You're oxidizing fatty acids for energy. You're eliminating the carbon primarily as CO2 and hydrogen as water. This is what shrinks your fat cells. so not n- necessarily anything you need a memory is there. But we wanted to emphasize that it's not as simple eat less, burn fat, lose weight. And it's not just about how long can you be in a deficit. It's about creating a deficit that is large enough to produce meaningful fat loss, but also sustainable enough to preserve your muscle, your activity, manage your hunger, support your training, and eventually transition to a maintenance phase.

Brianna 16:27

Mm-hmm.

Baylee 16:27

And those are all things that we just want you to think about where there are a lot of times if you have been in a deficit and you're like, "Oh, not happening anymore. Should I go lower? What, what needs to change?" Oftentimes you might need to go back to maintenance for a little bit to get out of those adapt- adaptations and rev your metabolism up some more

Brianna 16:48

Yeah. And I, I wanna emphasize this because I've had so many people this past week... It's only Tuesday. It's only Tuesday. That's insane. Monday was a long day. That are, like, now in their 40s, sometimes 50s, and the whole, like, "It used to be so easy to lose weight when I was in my 20s." It's gonna take a little longer because your body is a machine. Cellular signaling has slowed down. Maybe your cell health isn't as great. All this is becoming... You gotta, you gotta put in a little extra work for it to happen. So there's a lot going on, which is why we're always like, nothing is happening just by itself. We're not a vacuum. There's a lot going on. It takes time, and this is why you wanna be having your body work as efficiently as it can because all this is a lot of process. You don't wanna... You're not gonna get there overnight. Your body isn't made for that. It's just not.

Baylee 17:41

It's gonna backfire.

Brianna 17:42

Yeah

Baylee 17:43

this is exactly where our next episode is gonna be about how to target fat loss.

Brianna 17:48

Угу

Baylee 17:49

make sure you come back next week. We'll do a little kind of like part two to this with now that you understand what's actually going on, it's not just like pooping out our fat all the time or I don't know. But

Brianna 18:01

Yeah.

Baylee 18:01

there,

Brianna 18:02

sweating it out in the sauna.

Baylee 18:03

yes.

Brianna 18:04

Yeah

Baylee 18:05

Now that you know that there is truly a process to losing fat, we're gonna teach you how to really target fat loss. So

Brianna 18:13

That'll be a good one

Baylee 18:14

next week with a brand new episode, and we'll talk to you later. Bye.

Brianna 18:19

Bye