Keto And Fasting: Working Out While In Ketosis

The ketogenic (keto) diet and intermittent fasting are two of the most popular health trends. Both are used by health-conscious consumers looking to manage their weight and support their general well-being. While the keto diet is a high-fat, very low-carb way of eating, intermittent fasting is an eating method that cycles between calorie restriction and normal food consumption during a specific time period.

Combining the two methods is likely safe for most people and can help the body reach ketosis faster, which may lead to additional weight loss. However, it is important to note that this combination may be too restrictive and challenging for some people. It is always recommended to consult a healthcare professional before starting any new diet or fasting protocol.

What is intermittent fasting?

Intermittent fasting is an eating pattern that cycles between periods of fasting and eating. It is not a diet in the traditional sense, as it does not specify which foods you should eat, but rather when you should eat them.

There are several ways to practice intermittent fasting, but they all involve splitting the day or week into designated eating and fasting periods. During the fasting period, you won't eat anything, but you can usually drink calorie-free beverages like water, herbal tea, and black coffee.

• The 16/8 method: This involves eating only during an eight-hour window each day and fasting for the remaining 16 hours.
• Eat-stop-eat: This method involves fasting for a full 24 hours one or two days a week.
• The 5:2 diet: On this plan, you consume only 500-600 calories on two non-consecutive days of the week and eat as usual for the remaining five days.

Intermittent fasting is primarily used as a weight-loss technique, but studies have shown that it may benefit health in several other ways, including reduced inflammation, improved brain function, and better blood sugar control.

What is the keto diet?

The keto diet, short for the ketogenic diet, is a low-carb, high-fat diet. The diet drastically reduces carbohydrate intake and replaces it with fat. Typically, 70% of the diet is made up of fat, 20% protein, and only 10% carbs. This reduction in carbs puts the body into a metabolic state called ketosis, where it becomes very efficient at burning fat for energy.

The keto diet was originally designed in the 1920s to help control seizures in children with epilepsy. It has also been used to treat other neurological disorders like Alzheimer's disease, Parkinson's disease, and sleep disorders.

Today, the keto diet is a popular weight loss strategy. It is also linked to other potential health benefits, such as lowering the risk of certain diseases. For example, the diet can help improve risk factors for heart disease, including body fat, HDL (good) cholesterol levels, blood pressure, and blood sugar.

There are several versions of the keto diet, including the standard ketogenic diet (SKD), the cyclical ketogenic diet (CKD), the targeted ketogenic diet (TKD), and the high protein ketogenic diet. The SKD is the most researched and recommended version.

On the keto diet, meals are based on meat, fish, eggs, butter, nuts, healthy oils, avocados, and low-carb vegetables. It is important to moderate protein consumption, as too much can slow the transition into ketosis.

While the keto diet can be effective for weight loss and improving health, there are also some potential risks and side effects. These include nutrient deficiencies, liver problems, kidney problems, constipation, and fuzzy thinking or mood swings. Therefore, it is important to consult a doctor and a registered dietitian before starting the keto diet.

How to combine the two diets

Combining the ketogenic diet with intermittent fasting is likely safe for most people, but it is important to consult your healthcare provider before making any major dietary changes. This combination may not be suitable for pregnant or breastfeeding women, those with a history of disordered eating, or those with certain health conditions, such as diabetes or heart disease.

• Start with keto: It is generally recommended to start with the ketogenic diet first before adding intermittent fasting. This allows your body to adjust to burning fat for fuel and can help you avoid hunger during fasting periods.
• Ease into it: If you are new to intermittent fasting, start with a shorter fasting window, such as 12 or 14 hours, and gradually increase the duration as you become more comfortable.
• Choose the right timing: Consider aligning your eating window with daylight hours, typically around 8 hours, and fasting during the night. This aligns with our natural internal clocks and supports our circadian rhythms.
• Focus on whole foods: Emphasize whole, unprocessed foods, including healthy fats, low-carb vegetables, and adequate protein sources such as meat, poultry, or tofu. Avoid highly processed "keto" snacks and focus on nutritional quality.
• Stay hydrated: Drink plenty of water, tea, or coffee during your fasting periods to stay hydrated. You can also consume small amounts of nut milk or cream in your coffee, as long as it stays under 50 calories.
• Monitor your body's response: Pay attention to how your body responds to the combination of diets. Measure your blood sugar and ketone levels, track your sleep, and make adjustments as needed.

Potential benefits of combining the diets

Combining the ketogenic diet with intermittent fasting may offer several benefits, but it is important to note that there is a lack of rigorous research on this approach. Here are some potential benefits of combining these two diets:

• Enhanced Weight Loss: Intermittent fasting boosts metabolism and promotes thermogenesis, which can lead to increased fat loss. Combining it with the keto diet may help you reach ketosis faster and burn more body fat.
• Improved Brain Function: The keto diet has been linked to improved cognitive function and reduced risk of Alzheimer's disease. Intermittent fasting may also enhance brain health by promoting the generation of new neural cells and increasing Brain-Derived Neurotrophic Factor (BDNF).
• Better Blood Sugar Control: Both keto and intermittent fasting can help stabilize blood sugar levels and improve insulin resistance. This combination may be especially beneficial for people with type 2 diabetes or prediabetes, but it is important to consult a healthcare professional before making any dietary changes.
• Increased Metabolic Flexibility: By combining keto and intermittent fasting, your body becomes more metabolically flexible, easily switching between burning sugar (glucose) and ketones (from fat) depending on the available energy source. This can lead to better weight management and improved exercise performance.
• Improved Cardiovascular Health: Intermittent fasting has been shown to reduce cholesterol, LDL cholesterol, and triglyceride levels, which are risk factors for heart disease. Combining it with the keto diet, which is also associated with improved heart health, may further enhance these benefits.
• Reduced Inflammation: Intermittent fasting has anti-inflammatory effects and can lower biomarkers linked to inflammation, such as CRP. Reducing inflammation is crucial as it is often referred to as "the root of all disease."
• Autophagy: Autophagy is a process where the body gets rid of damaged cells, bacteria, and viruses. Intermittent fasting induces autophagy, which may have longevity benefits and reduce the risk of aging-related diseases.
• Convenience and Simplicity: For those already following the keto diet, adding intermittent fasting can simplify meal planning, preparation, and cleanup. It can also be a natural progression for those who feel satiated eating high-fat foods and don't mind shrinking their eating window.

Potential drawbacks of combining the diets

Combining the keto diet with intermittent fasting can be challenging, and it may not be suitable for everyone. Here are some potential drawbacks to be aware of:

Restrictive Nature and Difficulty

The keto diet is already quite restrictive, requiring a significant reduction in carbohydrate intake. Adding intermittent fasting to this can make the diet even more challenging. Not everyone will feel comfortable restricting their food intake, and some may find it difficult to stick to the fasting schedule. It requires a lot of willpower and discipline to follow both diet plans simultaneously.

Blood Sugar Concerns

Combining low-carb intake with extended periods of fasting can cause dips in blood sugar levels. This can be dangerous for individuals with glucose metabolism issues or diabetes. It is crucial to consult a healthcare professional before attempting this diet combination if you have any underlying health conditions, especially related to blood sugar regulation.

Nutritional Deficiencies

Both keto and intermittent fasting restrict food intake, and if not carefully planned, this can lead to severe nutritional deficiencies. It is important to ensure you are still getting adequate vitamins, minerals, and fiber. A well-planned meal strategy is essential to avoid these potential deficiencies.

Ketoacidosis

In rare cases, blending a strict low-carb diet with prolonged fasting has been associated with a condition called 'starvation ketoacidosis' in individuals with type 2 diabetes. Ketoacidosis increases blood acidity, which can be life-threatening. This is a rare but serious potential complication that underscores the importance of consulting a healthcare professional before embarking on this diet combination.

Social Challenges

Strictly adhering to intermittent fasting schedules can pose social challenges, such as missing out on meals with friends and family. This may make it difficult to maintain social connections and could impact your overall well-being.

Individual Differences

Everyone is unique, and some people may find they can easily follow a keto diet but struggle with intermittent fasting, or vice versa. It is important to understand your individual needs and restrictions. Some people may find that combining both diets is too challenging or unsustainable for them.

Frequently asked questions