So confused. How does your body actually lose fat?
fromnebraska
Posts: 153 Member
I've been reading about the keto diet and how limiting carbs reduces your need for glucose and instead uses fat as an energy source. But how does weight loss work if you aren't doing keto? What is your body actually doing?
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Replies
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Breathing it out.
Science side of MFP, please explain!9 -
burning whatever fuel is most readily available.0
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The entire point of a calorie deficit is that it's going to induce your body to use the energy you've previously stored in your body (fat).5
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My amateur layman's understanding. Not meant to be scientfically precise. The calories you intake aren't enough to fuel your body for the day (deficit). So your body goes to fat reserves (and muscle) to make up the difference it needs to fuel.8
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So why are people bothering with this crazy keto thing if they can lose weight by eating a large variety of foods?47
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It does the same thing but not as quickly. Your body can handle a certain amount of carbohydrate - it's after that that it begins to be stored as glycogen, which needs to be burned off first before the fat gets used. So in a regular "diet" you'd ideally have the appropriate amount of carbs - or I guess if you go a little over you don't have that much to burn off first (the rest is used to fuel your body). In keto you don't have those carbs/glycogen to burn off so you just torch the fat straight away. Fat is less appropriate than carbs in terms of fuelling your body so I'm not sure of the long term health risks with keto (if any known), but I imagine someone here will be able to explain that a bit better.
EDIT: I have since been informed (thanks to those that did) that much of this is incorrect. Leaving it up for accountability but please disregard.27 -
You never actually lose fat cells per say. The energy in them is drained and they shrink. The body is fuel flexible and can survive on any macro. Best of luck. The body will take the fat energy and convert it to ketones bodies in the liver. Fatty acids I believe. The same happens when you eat a low fat diet. What people do not realize is their body will actually produce ketones when they sleep at night. The liver will also take protein and convert it to glucose. That's what I understand. I could be wrong.3
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Keto utilizes dietary fat not stored fat unless in a calorie deficit. If you look at the macros for it, it is high fat, moderate protein and low carb. But it still requires a calorie deficit.
In the hierarchy of how our bodies use nutrients, with balanced intake, our bodies preferentially use protein for tissue repair and building, carbs for energy and fat as a last resort for energy. Our bodies prefer not to store proteins and we store unused carbs as glycogen, if at all. Calories that get stored as fat are mainly....fat.
In a calorie surplus, we store mostly dietary fat. In a calorie deficit, we can burn stored fat as well as glucose/ glycogen and in extreme deficits, proteins (muscle tissue) for energy.
Depending on the intensity of our activity level, we are burning some mix of fat and glucose all the time. The higher intensity the more glucose, the lower the intensity, the more fat. Our body just shifts the fuel substrate automatically depending on demand.
The bottom line is, if you take in less energy than your body burns, your body will pull from energy stores to make up that deficit. A high percentage of that will be fat. This is true keto or not. There is not metabolic advantage to keto for fat burning. There may be other advantages for preference, compliance or insulin sensitivity in the obsese/ overweight/ pre-diabetic. But not for fat loss.6 -
fromnebraska wrote: »So why are people bothering with this crazy keto thing if they can lose weight by eating a large variety of foods?
Here are a few potential reasons:
- They read the bogus fad articles about the magical qualities of keto (which are usually greatly over-exaggerated)
- They try it, rapidly start dropping water weight and think they're losing fat super quickly and get excited
- They find fat and protein satisfying and are able to naturally stick to a calorie deficit much easier
- They prefer a structured, rigid way of eating (some people actually do thrive on a structured diet plan)
- They enjoy the actual scientifically-studied benefits of keto (people who suffer from PCOS or seizures)24 -
fromnebraska wrote: »So why are people bothering with this crazy keto thing if they can lose weight by eating a large variety of foods?
Because people advertise keto like it's an easier way to lose than it is. On paper, it looks like your body is going to immediately start burning YOUR fat stores for energy. In reality, it's going to first burn through all the carbs you consumed that day (which will be very little), then all fat that you consumed that day (which with keto is a significant amount) before turning to your stored fat. With a non-keto diet, your consumed carbohydrates will be higher and your consumed fats typically lower, but all of that still needs to be burned through before your body burns its own fat.
The technical part aside, if you consume 1500 calories a day and your body burns 2000 a day, you'll lose a pound a week whether you get all of those calories from bacon and eggs or all of those calories from strawberries and white rice.
People doing keto do lose a ton of water weight the first two weeks though, so it seems better up front, and if they go off keto they gain it back, but water weight =/= fat.9 -
Hello! I'm from Nebraska too.
When you're in a calorie deficit - meaning your intake of calories is less than your output of calories (TDEE) - your body uses your excess fat stores to supply the energy it's not getting from food consumed. Essentially, when keto works for weight loss, it's because the person eating a keto diet is also eating at a calorie deficit. There are other benefits to eating keto for some people (like those with epilepsy) but for most people eating a certain way such as keto, low-carb, etc., is not necessary... eating at a calorie deficit is.
I'm a slow typist so by the type I post this there will probably be a post by someone that explains this more succinctly than I did.
I will say if you're interested in keto, make sure and do lots of reading and fact checking. There's a lot of woo/bro-science out there, and some people make a lot of assertions about it that are not true.4 -
Look at your body like an engine. To move it burns fuel, which is transformed in energy and heat. The body is an engine that takes three main groups of fuels: carbs, fats and protein. The body derives this from food
Like an engine the body has a prefered fuel: carbs. The body can readily access carbs, they need less energy to transform in energy. This is why the body will burn carbs over protein and fat. The energy that is not used will be stored in the fat reserves to be used up later. When the body doesn't get enough calories it will turn to the fat reserves to keep going, this is when we lose fat.
The principle of Keto is that the body is deprived of its quick access fuel, carbs. To keep quick energy running the body will adapt and start to burn more fat. The burning of fat will release ketones, which create a ketosis state. The professional opinion whether or not keto diet is healthy differ. If you have a demanding job, excercise a lot or have a high demand for energy I wouldn't recommemd it. My personal opinion of Keto is that it is a bit of a fad diet and way to restrictive. But hey some people like it....3 -
fromnebraska wrote: »I've been reading about the keto diet and how limiting carbs reduces your need for glucose and instead uses fat as an energy source. But how does weight loss work if you aren't doing keto? What is your body actually doing?
keto and any other diet work exactly the same way...calorie deficit. You have to be in a calorie deficit to lose fat.
A calorie is a unit of energy...you require XXXX units to maintain the status quo. When you consume energy in excess it is stored as body fat...body fat is just energy stores...it's like your backup generator. When you consume less energy than your body requires, that deficiency has to be made up...so your backup generator kicks on and you burn fat as energy.fromnebraska wrote: »So why are people bothering with this crazy keto thing if they can lose weight by eating a large variety of foods?
A variety of reasons...many are simply misguided...it's about the biggest diet fad/trend going at the moment and there are always people jumping from one trend to the latest and greatest trend...about 5 years ago it was Paleo/Primal. A lot of people don't actually research it and think it turns them into a "fat burning machine" and nobody else is burning fat...when in reality, it's the fact that they are in a deficit that results in burning body fat...they're just using dietary fat for fuel and making ketones instead of glucose...but yeah, people are morons.
Some people have to have a "religion."
For some people it helps with adherence because they supposedly feel more satiated...not sure if it's true or just placebo...I personally am more satiated eating a balanced diet consisting of a wide variety of foods and plenty of complex carbohydrates.
It can be beneficial but hardly a necessary WOE for certain medical conditions.1 -
fromnebraska wrote: »So why are people bothering with this crazy keto thing if they can lose weight by eating a large variety of foods?
Some people find that a ketogenic diet makes it easier for them to be in a deficit (because it helps control their appetite). Some people are attracted to novelty and like trying new diets. Some people have accepted the theory that keto is required for weight loss or is a path for weight loss that doesn't require a calorie deficit.2 -
This is a cool article about what happens when your body burns fat, on any diet: https://www.npr.org/sections/health-shots/2014/12/16/371210831/when-you-burn-off-that-fat-where-does-it-go6
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dangernene wrote: »It does the same thing but not as quickly. Your body can handle a certain amount of carbohydrate - it's after that that it begins to be stored as glycogen, which needs to be burned off first before the fat gets used. So in a regular "diet" you'd ideally have the appropriate amount of carbs - or I guess if you go a little over you don't have that much to burn off first (the rest is used to fuel your body). In keto you don't have those carbs/glycogen to burn off so you just torch the fat straight away. Fat is less appropriate than carbs in terms of fuelling your body so I'm not sure of the long term health risks with keto (if any known), but I imagine someone here will be able to explain that a bit better.
You're not "torching" body fat though...you're torching dietary fat and making ketones...this is the part that a lot of people who just jump in fail to understand...the calorie deficit aspect is what is burning body fat.
The only difference in "quickly" is the initial water weight loss (it's not fat, so who cares)...after that, someone on keto will lose at the same rate as someone doing any other diet...long term studies prove this out.11 -
dangernene wrote: »It does the same thing but not as quickly. Your body can handle a certain amount of carbohydrate - it's after that that it begins to be stored as glycogen, which needs to be burned off first before the fat gets used. So in a regular "diet" you'd ideally have the appropriate amount of carbs - or I guess if you go a little over you don't have that much to burn off first (the rest is used to fuel your body). In keto you don't have those carbs/glycogen to burn off so you just torch the fat straight away. Fat is less appropriate than carbs in terms of fuelling your body so I'm not sure of the long term health risks with keto (if any known), but I imagine someone here will be able to explain that a bit better.
None of the bolded is accurate. There is no advantage in speed of fat burning to keto. And your body does not use glycogen as a fuel source preferentially to depletion before fat burning starts. Heck you burn primarily fat to fuel your metabolism when you sleep!!
And in keto, the fat being burned is primarily dietary fat and not stored fat.6 -
Bumping this so I can read when I'm off work...! 0
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Thanks everyone! That was very helpful. I was thinking incorrectly about the keto diet burning most body fat vs dietary fat.9
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If eating keto is satisfying for you, go for it. But a calorie is still a calorie and fat is still fat. A deficit is still needed to get rid of it, whether it's reach via keto or otherwise. I've lost 100lbs in a little over a year and I eat the *kitten* out of carbs.4
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The only thing I will add to this about macro preference by the body. There was a study done in rats that showed after significant weight loss, their body's tended to store dietary fat easier and an increase in carb oxitazation. Like I have stated before, the study was rats and not humans. It might not translate to real world.0
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fromnebraska wrote: »So why are people bothering with this crazy keto thing if they can lose weight by eating a large variety of foods?
Good question for those who believe in keto.1 -
dangernene wrote: »It does the same thing but not as quickly. Your body can handle a certain amount of carbohydrate - it's after that that it begins to be stored as glycogen, which needs to be burned off first before the fat gets used. So in a regular "diet" you'd ideally have the appropriate amount of carbs - or I guess if you go a little over you don't have that much to burn off first (the rest is used to fuel your body). In keto you don't have those carbs/glycogen to burn off so you just torch the fat straight away. Fat is less appropriate than carbs in terms of fuelling your body so I'm not sure of the long term health risks with keto (if any known), but I imagine someone here will be able to explain that a bit better.
With the small amount of research I did on just the bulletproof keto coffee, it was found that a lot of people's cholesterol levels went way high after consuming it regularly. The article suggested that anyone thinking of doing keto get their cholesterol checked frequently. I will say that I tried the bullet proof coffee for a week. I didn't like how it sat with me. I didn't feel great and even felt deprived. I'm sure it was the lack of nutrients since I was consuming such a high fat drink and barely any actual food (as it's usually had in place of a meal at breakfast).1 -
Apologies for my inaccurate post above and thanks to those who corrected me! Every day's a school day (and that will teach me not to check my understanding before I go posting all over these things!)20
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Your body is a chemical engine, it breaks down chemical bonds in hydrocarbon molecules and captures some of that energy to do work while the rest is expended in waste heat.
When you literally burn (as in with fire) a pile of sugar what is happening is that the sugar molecule (C6H12O6) is interacting with oxygen (O2) and in the increased temperature this reaction created CO2 (which is a gas) and H20 (water, which in a fire evaporates and escapes as steam) and a lot of released heat. If you burn fat (which is just a hydrated carbon chain) the overall reaction and biproducts are essentially the same. You use oxygen to oxidize the bonds and release water and carbon dioxide and energy.
Your body carries out the exact same oxidative reaction but rather than using extreme temperature it uses enzymes to catalyze the reaction and couple it in such a way that less energy is wasted as heat and some is captured in a "currency" molecule ATP which can be coupled to other reactions to carry out the metabolic and biochemical functions of life. The waste products of this breakdown remain the same however, you take in oxygen and you release water and carbon dioxide. The carbon dioxide you breath out and the water is either used to help keep you hydrated or is excreted. There is a bit of waste heat as well which your body uses to maintain your body temp. In fact even in the case of zero activity your body is constantly utilizing some of its stored hydrocarbon fuel in order to generate heat to maintain your body temperature at 37 degrees C. Why 37 degrees? Because that is the optimal operational temperature for enzymes that catalyze those biochemical metabolic reactions.
So where does the weight go? Well your body is constantly exchanging matter with its enviornment through intake of food and water, excretion (urine, feces) as well as through breathing. Water intake and excretion is homeostatic, meaning you have to maintain a certain amount of water in your body so water intake might temporarily increase your weight but you will excrete it later to come back into balance so it can be ignored. Feces are just what is left from digestion and were never really "inside" you, they are just what is left in the tube that passes from your mouth to your *kitten* so that can be ignored as well. All that is left therefore is breath. You breath in oxygen, which is O2 and you breath our carbon dioxide, which is C02. If the carbon you are exhaling is more than the amount you are taking in from your hydrocarbon fuel sources then you will lose weight, if it is equal you will maintain and if it is higher then you will gain weight. The amount of carbon dioxide you expel is proportional to the level of metabolic activity your body is under which is influenced by your activity level. Where does the weight go when you lose weight? You breath it out through that extra carbon atom. Where does the weight go when you gain weight? The excess is converted to fat (a hydrocarbon) and stored in triglyceride storage molecules. Doesn't matter if your intake is "keto" or not.
I gave a much more in depth version of this here:
http://community.myfitnesspal.com/en/discussion/10616800/biochemistry-answers-for-common-weight-loss-questions-what-are-macros-fats#latest38 -
Aaron_K123 wrote: »Your body is a chemical engine, it breaks down chemical bonds in hydrocarbon molecules and captures some of that energy to do work while the rest is expended in waste heat.
When you literally burn (as in with fire) a pile of sugar what is happening is that the sugar molecule (C6H12O6) is interacting with oxygen (O2) and in the increased temperature this reaction created CO2 (which is a gas) and H20 (water, which in a fire evaporates and escapes as steam) and a lot of released heat. If you burn fat (which is just a hydrated carbon chain) the overall reaction and biproducts are essentially the same. You use oxygen to oxidize the bonds and release water and carbon dioxide and energy.
Your body carries out the exact same oxidative reaction but rather than using extreme temperature it uses enzymes to catalyze the reaction and couple it in such a way that less energy is wasted as heat and some is captured in a "currency" molecule which can be coupled to other reactions to carry out the metabolic and biochemical functions of life. The waste products of this breakdown remain the same however, you take in oxygen and you release water and carbon dioxide. The carbon dioxide you breath out and the water is either used to help keep you hydrated or is excreted. There is a bit of waste heat as well which your body uses to maintain your body temp. In fact even in the case of zero activity your body is constantly utilizing some of its stored hydrocarbon fuel in order to generate heat to maintain your body temperature.
I gave a much more in depth version of this here:
http://community.myfitnesspal.com/en/discussion/10616800/biochemistry-answers-for-common-weight-loss-questions-what-are-macros-fats#latest
Why on Earth did this get wooed? It's the least woo-y answer I've ever seen on these forums.18 -
dangernene wrote: »Apologies for my inaccurate post above and thanks to those who corrected me! Every day's a school day (and that will teach me not to check my understanding before I go posting all over these things!)
Thanks for taking it in with a good spirit!
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Aaron_K123 wrote: »Your body is a chemical engine, it breaks down chemical bonds in hydrocarbon molecules and captures some of that energy to do work while the rest is expended in waste heat.
When you literally burn (as in with fire) a pile of sugar what is happening is that the sugar molecule (C6H12O6) is interacting with oxygen (O2) and in the increased temperature this reaction created CO2 (which is a gas) and H20 (water, which in a fire evaporates and escapes as steam) and a lot of released heat. If you burn fat (which is just a hydrated carbon chain) the overall reaction and biproducts are essentially the same. You use oxygen to oxidize the bonds and release water and carbon dioxide and energy.
Your body carries out the exact same oxidative reaction but rather than using extreme temperature it uses enzymes to catalyze the reaction and couple it in such a way that less energy is wasted as heat and some is captured in a "currency" molecule ATP which can be coupled to other reactions to carry out the metabolic and biochemical functions of life. The waste products of this breakdown remain the same however, you take in oxygen and you release water and carbon dioxide. The carbon dioxide you breath out and the water is either used to help keep you hydrated or is excreted. There is a bit of waste heat as well which your body uses to maintain your body temp. In fact even in the case of zero activity your body is constantly utilizing some of its stored hydrocarbon fuel in order to generate heat to maintain your body temperature.
So where does the weight go? Well your body is constantly exchanging matter with its enviornment through intake of food and water, excretion (urine, feces) as well as through breathing. Water intake and excretion is homeostatic, meaning you have to maintain a certain amount of water in your body so water intake might temporarily increase your weight but you will excrete it later to come back into balance so it can be ignored. Feces are just what is left from digestion and were never really "inside" you, they are just what is left in the tube that passes from your mouth to your *kitten* so that can be ignored as well. All that is left therefore is breath. You breath in oxygen, which is O2 and you breath our carbon dioxide, which is C02. If the carbon you are exhaling is more than the amount you are taking in from your hydrocarbon fuel sources then you will lose weight, if it is equal you will maintain and if it is higher then you will gain weight. The amount of carbon dioxide you expel is proportional to the level of metabolic activity your body is under which is influenced by your activity level. Where does the weight go when you lose weight? You breath it out through that extra carbon atom. Doesn't matter if your intake is "keto" or not.
I gave a much more in depth version of this here:
http://community.myfitnesspal.com/en/discussion/10616800/biochemistry-answers-for-common-weight-loss-questions-what-are-macros-fats#latest
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Aaron_K123 wrote: »Your body is a chemical engine, it breaks down chemical bonds in hydrocarbon molecules and captures some of that energy to do work while the rest is expended in waste heat.
When you literally burn (as in with fire) a pile of sugar what is happening is that the sugar molecule (C6H12O6) is interacting with oxygen (O2) and in the increased temperature this reaction created CO2 (which is a gas) and H20 (water, which in a fire evaporates and escapes as steam) and a lot of released heat. If you burn fat (which is just a hydrated carbon chain) the overall reaction and biproducts are essentially the same. You use oxygen to oxidize the bonds and release water and carbon dioxide and energy.
Your body carries out the exact same oxidative reaction but rather than using extreme temperature it uses enzymes to catalyze the reaction and couple it in such a way that less energy is wasted as heat and some is captured in a "currency" molecule ATP which can be coupled to other reactions to carry out the metabolic and biochemical functions of life. The waste products of this breakdown remain the same however, you take in oxygen and you release water and carbon dioxide. The carbon dioxide you breath out and the water is either used to help keep you hydrated or is excreted. There is a bit of waste heat as well which your body uses to maintain your body temp. In fact even in the case of zero activity your body is constantly utilizing some of its stored hydrocarbon fuel in order to generate heat to maintain your body temperature.
So where does the weight go? Well your body is constantly exchanging matter with its enviornment through intake of food and water, excretion (urine, feces) as well as through breathing. Water intake and excretion is homeostatic, meaning you have to maintain a certain amount of water in your body so water intake might temporarily increase your weight but you will excrete it later to come back into balance so it can be ignored. Feces are just what is left from digestion and were never really "inside" you, they are just what is left in the tube that passes from your mouth to your *kitten* so that can be ignored as well. All that is left therefore is breath. You breath in oxygen, which is O2 and you breath our carbon dioxide, which is C02. If the carbon you are exhaling is more than the amount you are taking in from your hydrocarbon fuel sources then you will lose weight, if it is equal you will maintain and if it is higher then you will gain weight. The amount of carbon dioxide you expel is proportional to the level of metabolic activity your body is under which is influenced by your activity level. Where does the weight go when you lose weight? You breath it out through that extra carbon atom. Doesn't matter if your intake is "keto" or not.
I gave a much more in depth version of this here:
http://community.myfitnesspal.com/en/discussion/10616800/biochemistry-answers-for-common-weight-loss-questions-what-are-macros-fats#latest
Dude..
You are becoming my hero!3 -
I'm starting to get a little frustrated with the misinformation that people have and continue to propagate. basically, carbs are 100% the cause of obesity and diabetes. Eat carbs, blood sugar goes up, release insulin (or inject for some diabetics), INSULIN signals the body to store glucose in the blood AS FAT. as long as insulin is up, even if you are eating at a moderate calorie deficit, you will not burn body fat for fuel, instead, you will feel very hungry and your metabolism will slow down to match the reduced calorie intake.
So, to lose fat on high carb, low calorie diet, you have to be low enough calories in that your body needs food and has already burned through ALL that you have consumed and used all easy glycogen stores, so after at least 8-12 hours of not eating anything, finally blood sugar and insulin levels drop, and then (probably about 5 or 6 am by this time...) your body will convert a small amount of stored fat to energy. then you wake up, have breakfast and go back to high insulin and burning calories consumed and body still trying to store fat instead of burn it. This is a hard slow road, but it will eventually reduce weight.
To lose weight on a low carb diet, your body is never given enough carbs to fuel base metabolic needs, so it learns to burn fat for fuel. once you're in ketosis and always burning fat, your body can so easily burn excess body fat for fuel, you won't feel as hungry. without so much insulin all the time, your body won't store fat, even if you eat higher calorie.
I also would suggest you look into intermittent fasting and time restricted eating. You don't have to go crazy with the fasting for days on end, which is hard, but consider trying at least *12 hours each day no food, water only* and if you are on a strict low calorie, that probably means you have to give up evening snacks to stay under your limit, so this is pretty easy. If you can push that to about 16 hours each day no food, even better.
whatever diet you choose, be prepared to maintain it long term to maintain your goal weight.51
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