Keto Diet: Carb Crash Or Weight Loss?

The ketogenic diet is a popular way to lose weight and improve health. It involves eating a very low amount of carbohydrates, a high amount of fat, and a moderate amount of protein. While it is considered safe for most people, it can cause some side effects, including the keto flu or carb flu. This is a collection of symptoms that some people experience when they start the keto diet, as their body adjusts to a new fuel source and a new way of eating. Symptoms can include fatigue, nausea, headaches, gastrointestinal issues, and sugar cravings, and can last from a few days to several weeks.

The keto flu: a collection of symptoms experienced when starting a ketogenic diet

The keto flu is a collection of symptoms experienced by some people when they first start the keto diet. The symptoms can range from mild to severe and vary from person to person. The keto flu is caused by the body adapting to a new diet consisting of very few carbohydrates. This drastic reduction can come as a shock to the body and may cause withdrawal-like symptoms.

Symptoms of the keto flu

Symptoms of the keto flu can include:

• Diarrhea
• Fatigue
• Muscle soreness
• Cravings
• Nausea
• Constipation
• Headaches
• Irritability
• Difficulty sleeping
• Stomach or intestinal pain

These symptoms can start within the first few days of cutting back on carbs and typically last a few days to several weeks.

How to alleviate the keto flu

• Stay hydrated: Drinking plenty of water can help reduce symptoms such as fatigue and muscle cramping.
• Avoid strenuous exercise: It's important to give your body rest during the first week of the keto diet. Light activities such as walking or yoga may improve symptoms.
• Replace electrolytes: Consuming bone broth or potassium-rich, keto-friendly foods like leafy greens and avocados can help reduce symptoms.
• Get enough sleep: Fatigue and irritability are common symptoms of the keto flu, and lack of sleep can make them worse.
• Eat more fat: Eating enough fat will help reduce cravings and keep you feeling satisfied.
• Cut out carbs slowly: If you're having a difficult time adjusting, try reducing your carb intake gradually rather than all at once.

Carb withdrawal: the psychological component of craving carbs and the physical discomfort experienced in the first few days

Starting a keto diet can be challenging, and you may experience a range of physical and psychological symptoms as your body adjusts to this new way of eating. This period of adjustment, often referred to as "carb withdrawal" or the "keto flu," typically occurs within the first few days of starting the diet and can last for several days or even a few weeks.

Psychological Component of Craving Carbs

The psychological component of craving carbs during the initial days of a keto diet is significant. Our environment, such as the smell of baked bread or our favourite treats, can trigger cravings even if we are not nutritionally deficient. Additionally, hunger is a habit; if you usually eat a bowl of ice cream every night, your body will anticipate this ritual, and you will feel hungry at a particular time. This is a classic example of classical conditioning, where an external stimulus (the time of day) triggers a behavioural response (hunger).

Cravings for carbs can also be influenced by hormonal shifts, especially during the luteal stage of menstruation, when sweet cravings are common. Furthermore, emotional stress, major life changes, or overwhelming responsibilities can trigger the intake of high-sugar and high-carb foods. Eating refined and simple sugars encourages serotonin production, a neurotransmitter associated with positive feelings, making people more drawn to carbs as a coping mechanism.

Physical Discomfort in the First Few Days

In addition to the psychological component, there are physical reasons for craving carbs during the initial days of a keto diet. When you start the keto diet, you reduce your carbohydrate intake, which lowers your blood glucose levels. As a result, your body activates glucose backup systems to maintain normal blood sugar levels, but this compensation doesn't happen immediately, leading to a low blood sugar state called hypoglycemia, which triggers hunger.

Sugar withdrawal can also trigger intense cravings, and research has shown that eating sugar activates similar areas of the brain as addictive drugs. When you suddenly stop consuming sugar, your body craves more of it, leading to withdrawal symptoms.

The physical discomfort during the first few days of a keto diet can include:

• Fatigue and weakness
• Increased thirst
• Muscle cramps and spasms
• Headaches
• Stomach complaints, such as nausea, constipation, or intestinal pain
• Difficulty sleeping

To summarise, starting a keto diet can lead to both psychological and physical challenges. Understanding the underlying causes of carb cravings and physical discomfort can help you prepare and manage these challenges effectively. Remember to focus on adequate sleep, hydration, and nutritional adjustments to curb cravings and improve your overall well-being during this transition period.

Thyroid hormone imbalance: reduced levels of thyroid hormones T3 and T4 can cause brain fog, chills and fatigue

When starting a ketogenic diet, some people may experience a "carb crash" or "keto flu". This is a collection of symptoms that occur when the body adapts to a new diet consisting of very few carbohydrates. Carb crash can include symptoms such as fatigue, muscle soreness, and cravings.

Now, onto thyroid hormone imbalances. Thyroid hormones (including T3 and T4) impact nearly every aspect of the brain, including neurogenesis (the production of neurons). A decrease in thyroid hormones can, therefore, impact brain function and cause brain fog. Brain fog is a group of symptoms that include low energy, forgetfulness, sleepiness, and difficulty focusing. It is often associated with hypothyroidism, but it can also be reported by patients with other medical conditions, such as lupus, chronic fatigue syndrome, COVID-19 ("long COVID"), and depression.

In addition to brain fog, reduced levels of thyroid hormones T3 and T4 can also cause chills and fatigue. Hypothyroidism is associated with feeling tired, cold, and sluggish, along with weight gain, dry skin, and constipation. These symptoms often resolve with thyroid hormone replacement therapy and the return of thyroid hormones to the normal range.

Cortisol increase: the stress hormone rises, causing irritability and trouble sleeping

Starting a keto diet can lead to a rise in cortisol, the body's main stress hormone. This is because limiting your carb intake causes a starvation response in the body. In an attempt to increase energy levels, the body triggers the release of stress hormones like cortisol. This increase in cortisol can negatively impact your mood and sleep, causing irritability and trouble sleeping.

Cortisol is produced and released by the adrenal glands, which sit on top of your kidneys. It is one of the body's "fight-or-flight" hormones, along with adrenaline. When you experience a stressful or frightening situation, your adrenal glands start pumping out cortisol, preparing your body to take immediate action. Cortisol pumps glucose into your bloodstream for fuel, increases heart rate and blood pressure, and shuts off digestive and reproductive functions so you have more energy to deal with the stressor.

Outside of the short-term stress response, cortisol also regulates your body's daily functions. It helps control your blood pressure and heart rate and is part of the body's natural circadian rhythm, with levels typically highest in the morning to help wake you up and make you alert.

When you start a keto diet, the initial increase in cortisol is due to a temporary increase in gluconeogenesis, which is triggered by glucocorticoids like cortisol. This increase in cortisol may also be to ensure there is enough glucose for brain functioning, as the brain cannot use fatty acids for fuel.

Research shows that cortisol levels increase more during workouts when on a low-carb diet than when on other types of diets. This is likely due to the lack of available carbs, with three possible explanations:

• On a low-carb diet, glycogen stores are partially depleted, so cortisol increases to facilitate gluconeogenesis during workouts.
• During workouts on a low-carb diet, fat oxidation is higher, so cortisol may increase to induce lipolysis in adipose tissue.
• Working out stimulates the uptake of glucose by skeletal muscles, which causes cortisol to increase to preserve glucose for brain function.

Most of the evidence indicates that cortisol increases on short-term (less than three weeks) keto diets. Resting cortisol levels return to normal after approximately three weeks on a low-carb diet, but post-workout cortisol stays elevated.

While starting a keto diet may lead to an initial increase in cortisol, this is usually temporary. Once you are consistently in ketosis, your cortisol levels will decrease as you will be using alternative fuel sources like ketones and fat, and will have a greater capacity to spare glycogen (your body's sugar stores). Therefore, you will no longer need as much cortisol to promote an increase in blood sugar levels.

Dehydration: a lack of water can increase feelings of hunger and cause headaches

Dehydration is a common side effect of the keto diet. This is because the body stores carbohydrates in the form of glycogen, which binds to water in the body. When you reduce your carb intake, your glycogen levels plummet, and water is excreted from the body.

Drinking enough water is necessary for optimal health and can also help reduce symptoms of dehydration, such as fatigue and muscle cramping. Staying hydrated can also curb feelings of hunger and reduce the intensity of headaches.

A water-deprivation headache can cause pain throughout the head or be more localized to the front, back, or one side of the head. The pain tends to intensify when you bend your head forward or make other head movements, and even walking can make the headache worse. The exact reason why dehydration causes headaches is unknown, but it is possibly triggered by pain receptors in the meninges, the lining around the brain. When a person is dehydrated, fluid can shift out of the brain, exerting traction on the meninges, which could stimulate the pain receptors.

Drinking 16 to 32 ounces of water should relieve a water-deprivation headache within an hour or two. However, more prolonged or severe dehydration may require more fluids and lying down for several hours until the pain dissipates.

In addition to drinking enough water, eating kidney-friendly foods when hunger strikes can help manage cravings. Fiber-rich snacks that are low in fat and high in antioxidants are a great option. Examples include apples, berries, and red and purple-skinned grapes.

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