When you start eating a lot of carbohydrates after eating a ketogenic diet is the weight gain fat or just glycogen stores being refilled?
It happens in sequence.First the glycogen storage is filled plus the water needed to dissolve it. Since the glycogen PLUS water is 1 calorie per gram this part of the gain happens extremely fast. Also we each have a limited amount of storage that can only be estimated by how much water we lost in the first week when we switched to a ketotic plan like Atkins Induction.Second the body starts storing new fat.In one meal the body won’t start storing fat. In one day it takes huge amounts of calories to get the body to store fat. Starting day two, though, bets are off. This is one of several reasons why people who chose to cycle do 1 or 2 days per week of low fat high carb in their cycle and that they practice portion control on their carby days.
Does depletion of glycogen cause fat loss or muscle loss?
Wow you've asked a lot - I'll try and explain but will probably miss out a couple of points, so feel free to message if there are any gaps... Your body needs a certain amount of calories each day to maintain itself (basic I know, bear with). If you have less calories than that, the body will have to burn itself to make up the difference. What the body burns will be a mixture of fat and muscle. Now, assuming you don't cut your calories so much that you put the body into starvation mode, it will prefer to burn fats, rather than muscle for energy. However, the body needs more than energy to survive, and will also need protein etc. For this it will have to burn muscle, rather than fat -thus a major benefit of the low carb diet is that you can get more of your calories from protein, preventing catabolism (muscle breakdown). However, your body will also burn a combination of fat and muscle, although there are several tricks to ensure that it favours fat more and more. For example, weight training depletes your muscles of glycogen, meaning the body cannot get energy from them, and as such, jogging afterwards will burn a higher percentage of fat). If you are in a calorie deficit, your body will, by definition, be using all the glycogen present in your food but still require more from your fat and muscle. The problem with carbs is more that they cause an insulin spike, which promotes fat storage, so your body is less inclined to burn them. If you're in a calorie deficit you will lose weight, but if you're concerned about maintaining muscle, then it's a whole different ball game - I recommend looking into keto diets, which are designed to help protect muscle. Hope this helps
Why do some athletes eat high-carbohydrate foods the day before a competition?
energy
When we fast for more 12 hours, which is burned first, our fats or muscles?
Our body always burns a combination of carbohydrates (blood sugar, liver glycogen, muscle glycogen), fats (dietary fat, body fat), and amino acids (dietary protein, muscle).Another form of energy which is produced when liver glycogen stores are low is ketone bodies, which can be used by skeletal muscle, the heart, the brain and so on. This is particularly relevant in a fasting environment.It also interconverts one form of stored energy into another, for example it can produce sugar from amino acids, it can convert carbohydrates to fat to be stored as triglycerides and so on.Fasting experiments of more than 12 hours duration have been conducted in humans.Presuming there was adequate carbohydrate in the diet and in the last meal before fasting started, glycogen stores in the body will be reasonably full.This is what you are likely to be burning at a greater rate compared to proteins and fat in the first hours of the beginning of the fast.As time progresses carbohydrate stores become gradually depleted and a greater percentage of the energy you are burning comes from fat (both fat that you have eaten and body fat).This effect (deriving energy from fat) increases the longer the fast lasts. At this stage, you are likely to start producing ketone bodies which begin to be used as energy as well.The likelihood of burning protein (dietary protein and protein stored as muscle in the body, which gets broken down and circulates as amino acids in the blood) increases with an increased duration of the fast. If alternative forms of energy (carbohydrates, fats) are not sufficient to sustain energy production for body functions, protein comes next.Another factor which increases the likelihood of burning protein is physical activity during the fast. If you are fasting and exercising, the body is likely to derive some of its energy from muscle as well.To answer your question, fat definitely gets burned first when you fast for more than 12 hours. If you are fasting for several days and/or exercising during the fast, you are likely to burn some muscle as well. But even in this case, much more energy would be derived from fat than from muscle.
What happens to glycogen stores in a person consuming a ketogenic diet?
The goal of a ketogenic diet is to deplete muscle and liver stores of glycogen. When glycogen is depleted, hormonal changes take place – insulin levels decrease and glucagon, a hormone that promotes fat breakdown rises. In response, your body taps into stored fat as a major fuel source since glycogen isn’t available.Certain tissues in your body can’t use fat as a source of fuel, including your brain and retina inside your eyes. These tissues depend on glucose. As an alternative they can use ketone bodies formed from the breakdown of stored fat. As fat breakdown increases, cells begin to make ketone bodies. These ketones supply glucose-deprived tissues like the brain with the energy they need.Weight loss is rapid when you first begin a ketogenic diet. Most of the weight lost during the first week is water – not fat. As glycogen stores are depleted due to the minimal quantities of carbs you’re consuming, water is lost along with the glycogen since the two are bound together. As you might expect, fat loss occurs on a ketogenic diet since a ketogenic diet forces your body to break down stored fat as a fuel source. Insulin sensitivity also improves on a ketogenic diet.From: What is a Ketogenic Diet and Does It Offer Benefits? - Cathe FriedrichFor more info: The Eating Academy | Peter Attia, M.D.
How long after eating does the body run out of carbs and begin using fat for energy?
Update: This answer has generated more feedback than previously anticipated, so I will update a few things and try to answer the additional responses.After about 4 hours post-prandial, the body will begin relying on both stored glycogen, and gluconeogenesis (production of glucose from stored fat).For around these first 8-12 hours or so, the body is mostly relying on glycogenAt about 24-30 hours without food, gluconeogenesis is the only fuel source.At between 4 days to 1 week, your glucogenic substrates are pretty much gone and you are running on ketone bodies (condensed acetyl coA -your breath smells like acetone)Response to additional inquiry: A person’s fitness can have some effect on the body’s energy state and usage. Athletes for example, might have more stored glycogen overall, but keep in mind that if they have more muscle they also have an increased resting metabolic rate. Conversely, someone with an inborn glycogen storage disorder (e.g. McArdles) would have to rely on alternative pathways like increased lactic acid formation during exercise).Gluconeogenesis uses whatever substrates are handy in abundance. Muscle may be broken down for its alanine, or triglycerides for the glycerol.Disease states have a much larger impact than BMI, although (generally speaking) to have a BMI of 35 or greater, correlates highly with insulin insensitivity → in this condition, the body always thinks it is fasting, even when blood glucose is high after a meal. The net result is that gluconeogenesis occurs constantly, and much of the circulating glucose is being excreted by the kidneys. Diabetics are at a higher risk of developing ketoacidosis because of the inefficient usage/storage of glucose.
How long does it take for the human body to start breaking down fat for energy, while fasting?
Before you can start burning stored body fat, you need to deplete the liver’s glycogen stores as to signal the requirement for burning more energy.How fast you’re going to start burning body fat depends on the overall energetic demands and how fast you’re going to burn through that liver glycogen.There are 100–150 grams of glycogen in the liver which takes about 18–24 hours of fasting to be depletedExercising on an empty stomach makes you burn through liver glycogen faster thus allowing you to tap into your body fat stores faster as well. If you do fasted cardio in the morning you can start burning body fat within 12 hours of not eatingEating a low carb ketogenic diet allows you to deplete your liver glycogen while still eating. To lose body fat you’d still have to be eating at a caloric deficit but keto helps the liver tap into body fat fasterYour body starts breaking down stored fat for energy when it needs to compensate for a caloric deficit. That can happen by consuming fewer calories or burning more than needed for maintaining daily energetic requirements.That’s why you’ll be burning primarily your own body fat while fasting - you’re not eating (at a caloric deficit) and your liver glycogen is empty (take energy from body fat)My personal strategy includes:Eating a low carb ketogenic diet that maintains relatively low liver glycogen thus enabling me to start burning body fat faster.I also do intermittent fasting with one meal a day as to keep me in this fat burning more most of the dayLow intensity cardio and walking around throughout the day create a larger caloric deficit by simply moving aroundWorking out in a fasted state has a tremendous hormonal response for fat burning and longevityIn general, if I were to be eating a nice large meal the night before, I’d be burning body fat by the end of the next day.Here’s an article about - How Long Does it Take to Enter into a Fasted State After Eating - Siim LandStay EmpoweredSiim