Hungry While Fasting?
You want to lose fat, clear brain fog, or build healthy habits. Whatever your core goal is for fasting, you may be worried about one struggle more than anything else:
Hunger.
Hunger is the most powerful human instinct for survival. Evolutionally, through a variety of biological mechanisms, our bodies are designed to signal hunger during times when food is limited.
While this is a natural process, it’s important to note that not all hunger is the same. Environmental influences can impact our hormonal responses and convince us we need food immediately while, in reality, the underlying reason why we’re hungry might differ from a simple “instinct of survival”
Things to know:
• Adenosine triphosphate (ATP) is the chemical “energy” that fuels our body. We can’t store or eat ATP, so our cells are constantly producing and breaking it down to create energy.
• Two primary sources our body uses to produce ATP are carbohydrates (in the form of glucose) and fat (in the form of fatty acids).
• Our body makes a decision on what portion of carbs and fat to use based on a number of factors, but mainly on the immediate availability of carbs that comes from the food itself and from glucose stored in the form of glycogen.
“Why am I so hungry while fasting?”
1. Carb Dependency / Metabolic Inflexibility
Until 12,000 thousand years ago, none of the processed foods, fruits, or vegetables we have today existed. The carbohydrate (carb) sources were seasonal and occasional, and it was rare that our ancestors found a fruit tree or a beehive.
When they did access a source of carbs, our ancestors' bodies produced insulin and other hormones that told them to eat as much as possible. Any excess food was turned into body fat for later use, in case they were not able to find anything else to eat for a while.
When food was indeed scarce, their bodies tapped into the fat reserves, giving them the necessary energy for further hunts and food searches. This evolution took place over the course of millions of years, and our bodies had to learn how to switch efficiently between these two processes.
Now, let’s take a look at two scenarios. These are simplified, but will explain the subject well:
Person 1 - a healthy, metabolically flexible individual
This person does the following:
• Eats a healthy, complex carb diet
• Has a balanced feeding-fasting window
• Can easily switch between producing energy from either carbs or fat
Because their insulin levels drop often, they condition their body to switch between burning carbs and burning fat for energy. They can adapt their primary energy source according to the type of food that is available to them at that time.
When they eat a meal, their body uses some of the calories in the food to produce “immediate” energy. The spare calories are then stored in the form of glycogen and fat.
But, when they stop eating (between meals and during a longer fasting period) and insulin drops, the body easily taps into these stored sources of energy.
This means this individual is fat-adapted and has a healthy metabolism.
Person 2 - metabolically INFLEXIBLE, aka “carb dependent”
This person has a harder time because they:
• Eat frequently, do not fast
• Consume simple carbs and other processed foods
• Can only use glucose for energy
• Aren’t able to burn much fat (in some cases, none at all)
The reason why they are unable to (or, at least, rarely) burn fat is because they rely on energy that is created primarily from glucose.
Glycogen is the storage form of glucose and carbs in the body. It’s a limited source of energy accounting for 1-2% of total energy stores (roughly 300-400 grams).
When the glycogen stores of carb-dependent people run low, the body quickly re-activates signals of hunger to ensure glycogen storage is being refilled, instead of switching to burn fat.
After all, why would the body learn to go through the trouble of tapping into fat if it was continuously told that food is coming soon? 
2. Hormone Imbalances
Hormones regulate our metabolism and appetite, including how much we eat and what we crave. These processes are complex and a variety of hormones work together to ensure our survival. As a result, hormonal imbalances may trigger false feelings of hunger. Below are a somewhat simplified mechanism behind some of the hormones.
• Ghrelin + Leptin
Ghrelin is the appetite INDUCING hormone. It tells your body when to eat by signaling hunger.
Leptin, meanwhile, is the appetite SUPPRESSING hormone. It tells your body when to stop eating by signaling satiety - the feeling of fullness.
Levels of ghrelin and leptin are affected by the quality of our sleep, the amounts of lean and fat mass in the body, as well as the stress and toxins that we’re exposed to daily. An imbalance can lead to severe hunger and uncontrollable eating.
• Cortisol
Cortisol is the body’s primary stress hormone but it also plays a significant role in hunger.
When cortisol production is activated, it increases how motivated we feel. This influx of motivation also causes us to crave food. It’s no surprise, then, that higher levels of cortisol in adults have been found to predict weight gain.
• Cholecystokinin (CCK)
CCK is a lesser-known hormone that regulates gut function. Its chief purpose is to prompt the digestion of protein and fat.
During meals, CCK production signals satiety and feelings of fullness to limit short-term food intake. So, if your CCK hormone does not activate as it should, you may not feel satiated enough to stop eating.
• Neuropeptide Y
A brain peptide, one of the core functions of neuropeptide Y (NPY) is to regulate feeding. Case in point — an overactive NPY system has been linked to dietary-induced obesity in rats.
Though increased food intake, in general, is associated with high levels of NPY, cravings for carbs may be especially strong.
• Insulin
Chronically elevated levels of insulin - caused by a poor diet or constant snacking and food intake - prevent the body from “unlocking” fat as an energy source.
Instead, it relies on glucose (that comes directly from food) as an immediate energy source. This leads to intense hunger and unhealthy cravings.
Fasting helps to rebalance all of these hormones naturally, allowing for:
• Metabolic flexibility - a state where the body can easily and efficiently switch between sources of energy that are available at any given time.
• Healthy metabolism - where the levels of the hormones listed above are balanced and the metabolic processes run smoothly.
3. Nutrient Deficiencies
Have you ever found yourself craving spinach, salt, or some type of fruit? Or have you ever eaten a meal and felt full, yet still craved more food?
While severe hunger and food cravings can be a result of wide variety of psychological and physiological processes, sometimes the answer lays in a more subtle issue. Our body may be simply searching for missing nutrients.
The problem of “hidden hunger” — or micronutrient deficiencies — isn’t spoken about enough. The deficiency of just one essential nutrient may dysregulate metabolic pathways and negatively affect our hormones.
And yet, 9 out of 10 Americans are not getting enough micronutrients on a daily basis due to factors such as unbalanced diet, stress, exposure to toxins or nutrient-deprived fruits and vegetables.
Here are a few examples of how specific nutrients influence hunger and cravings.
• Minerals
People who are low in sodium may experience stronger cravings for salty foods, such as bacon, nuts, or cheese.
While there are many reasons for sugar cravings, sometimes zinc and chromium deficiencies can mask themselves as desire to eat sweets.
Whereas strong cravings for chocolate could point to a magnesium deficiency and cravings for dairy products may indicate a calcium deficiency.
• B-vitamins
B2, B5, and B6 may influence hunger through their role in the breakdown of carbohydrates, proteins, and fats, and production of neurotransmitters.
B12 deficiency is perhaps spoken of the most often, with extreme tiredness being a leading symptom of this deficiency. Naturally, experiencing heavy fatigue can lead to binge eating in an attempt to boost energy.
• Vitamin D
A lack of vitamin D can impede the function of leptin (the appetite-suppressing hormone), which may result in increased feelings of hunger. As Vitamin D deficiency is common during the winter, it’s recommended to supplement this vitamin in the colder, darker months of the year.
“Is it possible to curb hunger while fasting or do I have to put up with it?”
Let’s pause for a moment to think about this:
Would intermittent fasting have become such a widely used health protocol in recent years if fasters had to battle hunger pangs 16 hours a day?
Doubtful.
This brings us to the good news — severe hunger is a temporary issue that gradually decreases the more fat-adapted we become. But, in the meantime, there are a few things we can do to help the body when cravings feel overwhelming:
Ways to reduce hunger while fasting
1. Have a glass of still or sparkling water
Remember that thirst can mask itself as hunger. Don’t be surprised if the urge to eat disappears soon after drinking a glass of water.
2. Eat fewer carbs
Consider eating fewer carbs for dinner. This will ensure your body gets through glycogen stores more quickly, leading to higher fat burn, less hunger, and easier fasting.
3. Exercise
Just a single session of high-intensity exercise (60%+ of your max heart rate) has been shown to reduce levels of ghrelin (the hunger hormone) for up to 60 minutes after exercise. What’s more, exercising daily can improve the function of the appetite control systems and insulin sensitivity.
4. Prioritize 7+ hours of sleep each night.
Poor sleep is directly linked to high levels of cortisol and ghrelin, and lower leptin levels. This causes an imbalance in the two main hormones that affect how hungry you feel.
5. Have some salt (and other electrolytes)
Salt is made up of around 40% sodium and 60% chloride. Both are electrolytes and classed as essential nutrients. Consume around 2-4 grams of salt per day (depending on your exercise frequency) to keep your sodium and chloride levels topped up. If you mix around a half-teaspoon of salt in water, this should be enough for the day. It’s also sensible to supplement with other electrolytes such as magnesium, potassium, and calcium.
6. Consume tea or coffee.
While it’s not a magic bullet, the caffeine in tea and coffee acts as a stimulant, increasing levels of adrenaline. As a hunger-suppressing hormone, adrenaline may help to reduce hunger during the fast for a brief period of time.
7. Keep busy.
This is one of the most practical tips to reduce emotional or habitual hunger. The body’s internal circadian clock, as well as feelings of boredom and stress, may increase appetite. Keeping yourself distracted with activities will help to solve this issue.
“How can I keep my body healthy while fasting?”
Whether you plan to start with a 12-hour fast, 16-hour fast, or longer, make sure you’re properly hydrated.
Fasting itself leads to a loss of water. This is because every 1 gram of glycogen (that we burn while fasting) is bound to roughly 3 grams of water. The body can hold anywhere from 400-500 grams of glycogen, meaning we might lose up to 1.2-1.5 liters of water from fasting alone.
Less water also means fewer minerals for the body to rely on. So, the best advice would be to drink water and supplement with electrolytes to replenish the body and ensure proper cellular hydration.
Abstaining from food is already challenging enough, so you don’t want to be dehydrated and invite unnecessary stress.
Our Morning Boost drink has a well-balanced ratio of minerals, as well as their cofactors, to ensure your body and cells have what they need to function properly. It’s easy to prep, you only consume it once daily, and the best thing? It doesn’t break a fast!
With 23 ingredients — including essential micronutrients and electrolytes — it’s one of the easiest ways to stay well while fasting.
With love,
The Fasting Aid team.
