At any given moment, your body is either burning fat or storing it. Which of the two states you are in, depends on the hormones, insulin, and glucagon.
Energy metabolism is principally managed by the actions of two very important hormones, called insulin and glucagon. Insulin is the main storage hormone, the one that stimulates fat to accumulate in fat cells, whereas glucagon does the opposite, it makes stored energy available for use.
How do these hormones manage the processes of weight loss and weight gain? How do they impact on appetite control? More importantly, how can you manage your appetite and weight, by managing your metabolic hormones?
When is insulin released?
Insulin is a hormone secreted by the pancreas in response to glucose. All carbohydrates in the diet, like starches and sugars, are eventually converted to glucose. Different types of carbohydrates affect the amount of insulin that is released by the pancreas, following a meal or a snack.
Protein also stimulates insulin release, but how much insulin is released by protein, largely depends on the other components of the meal. The more carbohydrate there is in the meal, the more protein will contribute to increasing the insulin response to the meal. If carbohydrate is limited in a meal, then protein appears not to illicit a significant insulin response.
Fat in the diet does not stimulate insulin release, and the combination of fat and protein in a meal also does not appear to have a significant impact on blood concentrations of insulin when compared to carbohydrate, with or without the presence of protein.
Dr. Benjamin Bikman has a PhD in Bioenergetics and in this video he does a wonderful job at explaining why we should have a healthy respect for insulin. It is fairly technical, but it is well worth anyone’s time.
The work of insulin: Storage mode
When the insulin in your blood is raised, your body is saving up the energy for later, and this is a very normal process. The two main processes are called glycogenesis (glycogen storage, the way glucose is stored in muscle and liver cells) and lipogenesis (fat storage).
Think of insulin is the “master anabolic hormone”. When insulin is released, it stimulates uptake of glucose into liver, muscle and fat cells, where the glucose is converted to glycogen or to fat. Insulin places your body in storage mode. It also stimulates muscle growth, which is why it is a hormone often stimulated (and abused) by body builders.
Insulin also suppresses a the circulating concentrations of the hormone glucagon, which does the opposite of insulin. Insulin stops all fat burning and processes, and tells the body to utilise or store the incoming energy from the diet.
Insulin has other important functions too, like stimulating the release of leptin, the main satiety hormone. Leptin is produced and secreted by fat cells in the body. When everything works normally with your carbohydrate metabolism, you will have a meal, the meal will raise your insulin, the body will use what it can immediately and store the rest of the energy for later. It will signal your hypothalamus with leptin, that you have eaten and that your are no longer hungry. You may read more on the technical details in this academic publication.
When is glucagon released?
Following a meal, the energy that was immediately available has either been used directly by muscle cells, or stored successfully for later use. Following the storage phase, as the body requires energy for regular maintenance or physical activity, the concentration of insulin decreases and the concentration of glucagon starts to increase. Insulin has already done its job, made sure that the energy has been stored in all the right places, if you are healthy.
As the concentration of insulin decreases after a meal, glucagon starts increasing more and more, as your body progresses towards a fasted state. This is your body’s natural mechanism to make sure that it has enough energy available for normal metabolism or during exercise.
The work of glucagon: Freeing up stored energy
Glucagon does the opposite of insulin. It signals the liver, muscle and fat cells to utilise the stored glycogen and fat for energy. The body can only store a limited amount of glycogen (glucose), but it can store unlimited amounts of fat.
At rest, the muscle cells consume the majority of the available energy and it prefers fat as its primary fuel and it also uses a lot of fat when we do endurance exercise. The ratio between how much fat we use during endurance training and how much carbohydrate, is determined by your medium term dietary profile.
As the insulin levels continue to normalise to fasting levels, the glucagon levels will continue to rise to their fasting levels, or higher if physical activity demands it.
The hormonal similarities between fasting and exercise
During exercise the body requires stored energy to be released in order to meet the energy demand of the physical activity. During exercise, glucagon continues to liberate stored energy for utilisation and insulin remains low.
The same process occurs as you approach a fasted state after eating, albeit slower than when you are performing physical exercise. The hormonal processes are extremely similar.
The simple thing to remember here is that glucagon is the hormone that you need when you are trying to liberate stored energy. When you are trying to lose weight.
Your body spends most of the day relatively idle, and its preferred source of energy in this state, is fat. In order to utilise fat, you need glucagon to signal the body to make sure that there is fat available for energy.
Turning on glucagon, means turning off insulin
Glucagon is not controlled by us or our diets directly, but rather indirectly via the action of insulin. In order to increase glucagon, we need to limit insulin secretion. It is important to understand that these hormones exist in equilibrium. Their relative ratios change in response to eating, exercising or fasting, but neither ever disappears from circulation completely.
Insulin secretion is the primary signal to change the ratios between insulin and glucagon in the favour of insulin. Glucagon only rises again after insulin starts going down. Think about glucagon this way: “When the cat is gone the mouse comes out to play”.
The amount of insulin that is secreted, is a response to the amount- and type of food consumed. There are several ways by which we can shift the equilibrium of these two hormones in the favour of glucagon, more frequently and for longer periods of time, which is what we want for losing weight.
- Reduce the frequency of insulin secretion (that is why intermittent fasting has become such a popular and effective method for weight control), reduce snacking during the day, etc.
- Reduce the extent of insulin secretion after a meal — This is achieved by selecting meals and food combinations that will limit the amount of insulin that is secreted. The smaller the amount of insulin that is secreted, the quicker the body will get back to increasing the glucagon and start using stored energy.
That sounds simple! What’s the catch?
The problem for most of us is that if it were that simple to eat less, both in volume and frequency, we would not be having this problem.
I have explored the concept more extensively here, but the essence of it is that appetite is the result of your diet, a consequence, not an inherent feature of you, or your metabolism.
How much carbohydrate we can process safely, is different for every person. When we eat more carbohydrate than we can process safely, we dramatically shift the hormonal balance in favour of insulin.
If we do this too often and for too long, we reach a point that our muscle, liver, kidney and fat cells don’t respond to insulin quite the way they used to and our bodies respond by secreting more and more insulin, to deal with the increased glucose in our blood. Our bodies become resistant to the effect of insulin.
The insulin resistance snowball effect
When our bodies start becoming insulin resistant, we start to see a few things develop, gradually at first.
- We eat more in order to satisfy our hunger — Insulin promotes the secretion of leptin, a hormone that tells the hypothalamus that we are satiated. As we become resistant to insulin, we become resistant to the effect of leptin and our hypothalamus is no longer the receiving the signal for satiety as clearly as it used to. We tend to need to eat more carbohydrates to generate the “full” signal. The fat cells are the ones responsible for making leptin, and as the insulin resistance increases, the leptin secretion increases, but the hypothalamus is not listening, so we keep increasing the leptin to get ourselves to stop eating. Meanwhile, the fat cells are still receiving the “storage” signal, loud and clear!
- We get hungry more frequently — As we need more and more insulin to get our blood glucose under control, the high insulin levels cause the blood sugar to drop unexpectedly (called reactive hypoglycemia) and when this happens, our bodies go into a state of panic. The is when hunger anxiety strikes. We get hangry. We become irritable and the need to eat something feels urgent.
- We gain weight — We find ourselves in storage mode all the time and the only reprieve we have from the storage mode, is when we go to the gym, or when we sleep. The persistent storage mode we enter into, coupled with the frequent blood sugar crashes that sends us running for our lunchboxes at 10:00AM, makes us lethargic, makes feel unmotivated and reduces the chances that we will even make it to the gym.
The first step to gaining control of your appetite is to recognise that you have to get your body to stop turning on the master storage hormone so frequently and so aggressively.
You can control your weight by controlling your appetite. You can control your appetite by controlling your insulin. When glucagon is elevated, it will suppress your appetite and as the body starts using its own fat for energy, you will start gaining real control of your appetite and your cravings.
You do not have to starve yourself
Eat when you are hungry. Don’t ever go hungry. But have a healthy respect for insulin. Remember these facts.
- Dietary fat does not cause insulin to increase.
- Protein + fat does not cause insulin to increase remarkably.
- Carbohydrates cause insulin to increase.
- Protein increases the magnitude of the insulin response when eaten alongside carbohydrate.
- Carbohydrate + fat will put your appetite into overdrive by putting you into ultra storage mode. This is what junk food does to us.
The basics of appetite
It is extremely important to understand that feeling hungry is NOT equal to losing weight. When people think about losing weight, the very first thing they think about, the anxiety around how hungry they are going to feel.
You are losing weight when you aren’t hungry.
I will repeat.
You will lose weight when you aren’t hungry.
Think about it, next time you are in the gym. Before you start, you may be extremely hungry, but 10 minutes into your session, you start forgetting about food and you are focusing on your burning legs. During your last set, you are not thinking about food. Maybe you are tired, but you aren’t hungry. That is the feeling you should have when you haven’t eaten for several hours. Not the feeling that you get when it is 12:30PM and you have already had your lunch sandwiches at 10:00AM.
When you are in a healthy fasted state, you are not going to experience hunger in the same, a way that frightens you or makes you anxious. There is no point to being hungry. Later on when you gain control of your appetite, you will start to experience hunger completely differently and you will be able to delay eating. That is something else entirely. That is when people start telling you about it, like CrossFitters. How they haven’t eaten in 20 hours and aren’t hungry. They aren’t (only) rubbing your face in it, they are sincerely ecstatic about the fact their their appetites are no longer dominating their every routine.
What does that mean for your eating habits?
The easiest way to achieve reduced insulin levels, is a low carbohydrate, high fat diet. It takes care of all the details.
Avoid carbohydrates and sugar. And not pretend-avoid for three days out of the week. You will have to make a real effort. This is where you need to be disciplined. There are several resources out there to help with a journey of that sort.
If you want control of your appetite, take control of your insulin, by taking control of your carbohydrate consumption.
Accept it, you cannot have your cake and keto too.
Source: Article by Philip Marais (https://medium.com/@finmn/cannot-have-your-cake-and-keto-too-60c4e50d51dc)
Fasting is a powerful tool to decrease your insulin levels and to regain good insulin signaling very quickly; in this sense it’s even more efficient than the ketogenic diet., There are big benefits to be had with it, especially if you wish to control your blood sugars or lose fat.
A fat fast is a compromise from typical fasting. It’s as close as you can get to fasting without actually fasting.
What’s a fat fast?
It’s simple: during a water fast you drink only water, during a fat fast, you consume just fat. That would be the strict definition. But even on water fast you can drink black coffee, tea and, bone broth.
It basically comes out of doctors wanting their patients who fail to fast to still get some of the benefits from – so they compromise with a fat fast.
The very low-calorie meals in practice don’t just contain fat. The main reason for this is because no foods (besides oils) consist of 100% fat. Drinking oil (not even the holy extra virgin olive oil) is not something we recommend.
So if you’re finding typical fasting too hard, we suggest trying a fat fast where you eat foods that contain only a little bit of protein (and negligible amounts of carbs). You should aim for 80-90% of calories from fat and the rest from protein.
More details on what that looks like in practice below.
The traditional fat fast go back to Dr. Atkins and is high fat, low-calorie diet that involves 4-5 small meals and 1,000 -1,200 kcals per day. At Nutrita we don’t believe in calorie counting as a good way to control body composition and metabolism. We always recommend to eat until full even though this can vary quite a bit from person to person. Hence this modified version of the original fat fast we recommend people can try out if they’re failing to do a typical fast at first.
Fat fasting is like an extreme version of the ketogenic diet. You keep the carbs around zero and ramp up the fat like crazy and protein is kept relatively low. You might even abstain from lean meats entirely.
Carbs considerably raise insulin levels and even protein has an impact. Fat is the only macronutrient that has a tiny effect on raising insulin levels above fasting (basal) ones. This is why a fat fast allows you to keep your insulin extremely low despite eating.
What are the benefits of fat fasting?
Fat fasting gets you into ketosis quickly and deeply, not too different than with typical with. Because fat is very satiating, it suppresses your appetite. Being in ketosis also suppresses appetite, and fat fasting gets you even deeper into ketosis.
Ketosis is known as a state where you very efficiently use fat for fuel. So, on a fat fast, you maximize fat burning and maximally decrease your appetite. That’s an incredibly powerful combination for weight loss!
Fat fasting, like regular fasting, is a temporary, intermittent strategy. You can also think of it as a means to an end, or a useful signpost telling you how normal your appetite is. Intermittent fasting can also be thought of as the pattern of eating people naturally fall into when eating about twice a day, on average.
There are three good reasons to do a fat fast:
1 – A stepping stone to typical fasting
When fasting, most people are very hungry during the first two days. On day three, when glycogen stores are emptied, the body is forced to burn body fat as fuel. As most people have plenty of energy stored as fat, there is no energy shortage as soon as the fat stores are accessible. This is precisely the reason why you don’t feel hungry when fasting.
Insulin is the primary hormone that suppresses fat burning or lipolysis. Because you bring down your insulin levels on a fat fast, you optimize fat burning. Once your body is used to burning fat as fuel, it will also burn body fat more efficiently.
Fat is fat, and burning fat from the diet or body fat does not make a big difference. The only difference is accessibility. So a fat fast helps will help some people to bypass these first 2-3 days on a water fast, where you may reach peak hunger.
2 – Overcome a weight loss plateau
Many people initially lose a lot of weight when starting a ketogenic diet and then hit a weight loss plateau. Because the fat fast fat is even better for fat burning than a regular ketogenic diet, and at the same time decreases appetite and hunger, it helps you to overcome a plateau.
3 – Extreme hunger pangs and carb cravings
Most people feel less hungry on a ketogenic diet, and carb cravings tend to disappear very soon. However, everybody is different, and for some, this effect is less pronounced. Or it just takes longer.
In this case, fat fast is an option for overcoming this hurdle and starting to get some of the benefits from ketosis. So, a fat fast can be seen as a faster method than gradually reducing one’s carb intake. Or, a slower method than straight fasting to get into ketosis.
Other people find it easier to decrease their carb intake gradually.
What does science say about fat fasting?
The biggest fear with fasting is always losing valuable muscle protein. Because it’s such hard work to build up muscle mass, the last thing you want to do is to put it at risk through fasting. Thankfully, fasting shouldn’t be of much concern.
First of all, fasting shouldn’t be confused with a calorie-restricted diet; these all too often restrict high-quality animal protein excessively. Yes, technically speaking fasting is calorie restriction put to an extreme. There are benefits from removing calories alone and you will likely take up fewer calories than you expend on a fat fast. So isn’t fasting offering just more of what calorie restricted diets do for you over the long run?
No! Calorie restriction means not eating despite being hungry. If you don’t eat because you are not hungry, your body does not feel energy deprived.
To sum it up: the big difference to conventional calorie restriction is that fasting makes fat stores accessible and as a consequence, energy expenditure goes up instead of down.
Your body only burns muscle protein in an emergency situation. Muscle protein is a precious resource, and your body is not as crazy to burn it as long as it has access to significant fat stores.
For this reason, a well-timed regular fast, fat fast or just a ketogenic diet allow you to rely on fat for energy as well as preserve your muscle mass. Furthermore, fasting triggers the release of growth hormones and the ketogenic diet is known to have a muscle-sparing effect in calorie-restricted scenarios,, So, the ketogenic diet in combination with fat fasting or regular fasting can be fine to preserve muscle mass while losing fat.
How to fat fast the right way?
The most important rule: don’t count calories on a fat fast – that would be totally crazy and self-sabotaging. The fat fast is the exact opposite of a low-calorie diet – with good reason.
After a few days on it, your appetite decreases and your calorie intake will automatically normalize. And it will give you the confidence of going about your day with way less food. It’s a useful way to kickstart yourself into water fasting.
When starting the fat fast, you may still eat quite frequently. But remember, the point is to overcome hunger pangs and worries about not eating, not to fully feed yourself as you usually would. Very soon hopefully you’ll notice that you feel full for longer.
Listening to your body at this point is crucial.Don’t eat because it’s time to eat. Don’t eat because it’s a habit. Don’t eat when you are not hungry.
A fat fast is not dangerous, but it’s meant to be short-term. For a few days, it gives you everything you need to get as close as possible to a typical full fast. If you use eggs for instance, they’re incredibly energy-dense food, so you certainly don’t have to worry about nutrient deficiencies.
But the macronutrient distribution is skewed extreme, and as your appetite diminishes dramatically your protein intake will drop. That’s fine for a few days, but remember this way of eating is not sustainable long-term – it’s to help get into typical fasting. Do a fat fast for a few days, or one-week maximum.
It is crucial that you only eat healthy fats on a fat fast. You want to do something good for your body, and don’t want to inflame yourself! In brief, avoid high omega-6 seed oils and have animal fats mainly, like butter or lard.
To make it even easier for you: in the next section, you’ll find exactly what to eat on a fat fast.
What to eat on a fat fast
- Fatty fish (mackerel, herring, sardines, salmon)
- Butter, lard, ghee, olive oil, avocado oil, coconut oil, MCT oil
- Mayo (made from avocado oil)
- Lettuce and other leafy greens
As you can see, this list is very short and clear. As long as you stick to this list, there’s not much room for errors, and you cannot do anything wrong.
In case you need some inspiration, you find some easy recipes and a 3-day meal plan below.
- 3 eggs or more
- Salt and pepper
- A few leaves fresh basil
- 1 tablespoon of butter
Melt the butter in a pan on medium heat. Whisk the eggs and the remaining ingredients, and in the pan until your preferred texture is reached.
Optional: add some fried bacon as a side.
Alternative: fried eggs, poached eggs, boiled eggs…
Avocado oil is ideal for mayo because it contains healthy fats and, unlike olive oil, it does not have a strong taste of its own.
- 2 egg yolks
- 1 tablespoon of lemon juice
- 200 ml of avocado oil
- Salt & pepper
Whisk the yolks, ¼ teaspoon salt, and the lemon juice until combined well. Then start adding the avocado oil drop by drop while whisking constantly. After the first ½ cup of oil, you can add the oil in a slow, thin stream. The mayonnaise will be slightly yellow, thick and creamy.
Deviled eggs or egg salad
1 tablespoon mayo per egg
Boil the eggs for 4-6 minutes. For the deviled eggs, cut the eggs in half and spread with mayo. For the salad, cut the eggs into pieces and mix with the mayo.
Spinach with salmon
150 g fresh spinach, 250 g salmon
Salt, pepper & ground nutmeg, 1 tablespoon of butter
1 tablespoon of coconut oil
Melt the coconut oil in a pan on medium heat. Add the spinach, stir regularly and cook for about 5 minutes. Season with salt, pepper, and nutmeg.
Fry the salmon in a separate pan with the butter. Season with salt and pepper.
Optional: serve with sauce Hollandaise.
3-day meal plan
The 3-day meal plan is just an example to get you started. How many meals you eat per day and how much you eat totally depends on you and your hunger. Let your appetite guide you!
Scrambled egg with bacon
Salmon with spinach and sauce hollandaise
Green salad with avocado, olives and mayo dressing
Avocado mackerel salad
Green salad with olives, bacon, olive oil and 1 tablespoon lemon juice.
Salmon with spinach and fried bacon.
Green salad with olives, olive oil and 1 tablespoon lemon juice.
A fat fast is an excellent way to deepen ketosis, a large part of the benefit typical water fast provides. Fat fasting can be a good way for people to progress to a typical fast when struggling to make the transition. Fat fasting may also help you get rid of carb cravings. It is, however, a short-term method with a specific goal in mind.
Fat fasting is a temporary tool to help you get into typical water fast, and by its nature isn’t a balanced way of eating in a long-term perspective, For this reason, you may want to try it out for a few days, or a week maximum.
Source: Article by Sarah Neidler, PhD. Scientifically Reviewed by Raphael Sirtoli (https://nutrita.app/article/fat-fasting)