Cannot Have Your Cake And Keto Too

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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.

Cells of the pancreas: Nutritional Biochemistry — Tom Brody

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.

Dr. Benjamin Bikman — ‘Insulin vs. Glucagon: The relevance of dietary protein’

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.

Nutritional Biochemistry — Tom Brody

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

Nutritional Biochemstry — Tom Brody

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.

Insulin resistance.

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.

Think insulin!

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 (

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