Cardio On Keto: How Long Should You Go?

The ketogenic diet is a very low-carb, high-fat, moderate-protein diet that has been linked to a long list of potential health benefits, including weight loss, boosted energy, and improved blood sugar control. However, its effect on athletic performance remains controversial. While some claim that keto can enhance endurance and boost fat burning, others argue that it could drain energy levels and impair high-intensity exercises that rely on carbohydrates as fuel.

When it comes to cardio on keto, the type and intensity of the exercise, as well as individual factors such as fitness level and keto adaptation, will determine how long and how often you should perform cardio workouts. Low-intensity steady-state (LISS) cardio exercises, such as walking, jogging, cycling, or swimming, are generally well-tolerated on keto and can be performed for longer durations without experiencing fatigue. On the other hand, high-intensity interval training (HIIT) or anaerobic exercises, such as sprinting or CrossFit, may be more challenging due to the body's reliance on glycogen (carbohydrate stores) for fuel during these intense bursts of activity.

To optimize your cardio workouts on keto, it is recommended to start with LISS exercises and gradually increase the intensity as your body adapts to using fat for fuel. Aim for moderate-intensity physical activity, which is typically defined as maintaining a target heart rate of 50-70% of your maximum heart rate. You can calculate your maximum heart rate by subtracting your age from 220. For example, a 50-year-old person would have an estimated maximum heart rate of 170 beats per minute (bpm), with a target heart rate range of 85-119 bpm during moderate-intensity exercise.

Additionally, it is important to ensure proper nutrition and adequate calorie intake, especially consuming enough healthy fats and protein, to support your workouts and promote muscle recovery. You may also consider incorporating strength training or other forms of exercise into your routine to create a well-rounded fitness regimen that complements your keto diet. Remember to always listen to your body and adjust your workouts or nutrition as needed to achieve your health and fitness goals.

High-intensity exercises are more challenging on keto

The ketogenic diet is not ideal for high-intensity exercises and can impair performance. This is because the body's main source of energy for high-intensity activities is carbohydrates, which the keto diet restricts. When the body doesn't have enough carbohydrates, its ability to perform high-intensity exercises is affected.

During high-intensity exercises, the body relies on glucose (a form of sugar) for energy. With keto, the body switches to using ketone bodies created by breaking down fats in the liver. This process can take some time for the body to adjust, and during this transition, individuals may experience a decrease in energy levels and athletic performance.

Additionally, keto diets may not be optimal for muscle growth as they often involve restricting protein intake, which is necessary for muscle synthesis and repair. The diet may also be low in calories, making it challenging to consume enough protein to build muscle mass.

High-intensity exercises such as sprinting, boxing, swimming laps, jumping rope, weight lifting, and high-intensity interval training are more challenging on a keto diet. The body's ability to perform at high intensities for activities lasting longer than 10 seconds is impaired due to the lack of readily available glucose.

For individuals who engage in high-intensity workouts, it is essential to consume the right amount of fat and protein. Carbohydrates provide a muscle-preserving stimulus, and without them, adequate amounts of fat and protein are necessary to maintain performance and support muscle growth.

While keto may not be ideal for high-intensity exercises, it is important to note that the diet may enhance endurance performance. Some studies suggest that keto can improve physical endurance due to the body's increased ability to use fat as an alternative energy source. However, more research is needed to confirm these findings.

Keto may boost fat burn

The ketogenic diet is a high-fat, moderate-protein, and low-carb diet. It works by lowering insulin levels, producing ketones, and increasing fat burning. The body enters a metabolic state called ketosis, where it turns fats into ketones, which can supply energy for the brain.

Weight Loss

There is evidence that ketogenic diets can help with weight loss. They may help you lose fat, preserve muscle mass, and improve markers of disease. Some studies suggest that a ketogenic diet may be more effective than a low-fat diet for weight loss, even when matching the total calorie intake.

Fat Burning

Several studies have found that ketogenic diets may slightly increase the amount of fat you burn during rest, daily activity, and exercise, although more research is needed.

Appetite Suppressant

Ketogenic diets help you feel full. This is supported by positive changes in hunger hormones, including leptin and ghrelin.

Insulin Sensitivity

Ketogenic diets can drastically improve insulin sensitivity, which can help improve fuel utilization and metabolism.

Decreased Fat Storage

Some research suggests ketogenic diets may reduce lipogenesis, the process of converting sugar into fat. This is because excess carbs are stored as fat. When there is a minimal intake of carbs, fat is used for energy.

Metabolic Disease

Ketogenic diets can improve many aspects of metabolic syndrome, a major risk factor for obesity, type 2 diabetes, and heart disease. Insulin plays an important role in diabetes and metabolic disease, and ketogenic diets are effective for lowering insulin levels, especially for people with type 2 diabetes or prediabetes.

Inflammation

The ketogenic diet can drastically reduce chronic inflammation, which is linked to metabolic syndrome and various diseases.

Gut Health

Some studies indicate that maintaining a healthy bacteria balance in your gut can improve gut health, which may help reduce fat mass and inflammation.

Calorie Deficit

The only way to legitimately accelerate fat loss is to consume foods that help you maintain a calorie deficit without feeling fatigued, unhealthy, or hungry.

Cardiovascular Health

Ketogenic diets may also improve cardiovascular health by reducing insulin resistance, inflammation, and chronic disease risk.

You may feel less energised initially

When you start the keto diet, your body goes through a metabolic adjustment phase where it switches from burning glucose as its primary fuel source to burning ketones. This adjustment is called the keto flu and can leave you feeling less energised initially. The average adjustment period can take anywhere from one to three weeks, but listening to your body and scaling your workouts accordingly can help you ease the symptoms.

During this adjustment period, your body is training itself to burn fat for energy instead of carbohydrates. As a fuel source, fat is not as easily burned as carbohydrates, so the process is overall less efficient. This can lead to a decrease in energy levels, especially when performing high-intensity exercises.

The keto diet involves severely restricting your intake of carbohydrates, which are your body's main source of energy. Therefore, switching to a ketogenic diet can negatively affect your athletic performance and energy levels, especially as your body first begins adapting to using fat for fuel instead of carbs.

One small study found that athletes experienced decreased energy levels at the beginning of the keto diet, which gradually increased back to normal over time. Another study reported that increased levels of ketones in the blood could increase feelings of fatigue and decrease the desire to exercise.

However, this initial decrease in energy is usually temporary, and your body will adjust to using fat as its primary fuel source. In the long run, the keto diet may even help to improve your endurance during exercise and offer a faster recovery period after intense workouts.

Tips to Boost Your Energy Levels on the Keto Diet:

• Ease into your workout routine and scale your workouts during the adjustment period.
• Choose a keto-friendly pre-workout supplement, such as pure C8 MCT oil, which can provide a long-lasting energy boost.
• Opt for strength training or low-intensity, steady-state cardio activities, as these types of exercises use fat as their primary energy source.
• If you are doing high-intensity workouts, consider boosting your carb intake by consuming an additional 15-30 grams of net carbs from simple carbohydrates 30-60 minutes before your workout.
• Make sure you are eating enough, especially healthy fats, to properly fuel your workouts and support your body's needs.

Your body may burn more calories on keto

The ketogenic diet is a very low-carb, high-fat, moderate-protein diet that has been linked to a long list of potential health benefits, ranging from improved blood sugar control to decreased hunger levels. It is designed to put the body in a state of ketosis, where it burns fat as a fuel source, as opposed to running on carbohydrates.

A 2018 study found that when overweight adults replaced carbohydrates in their diet with fat for a period of five months, their bodies were able to burn approximately 250 more calories per day than people who ate high-carbohydrate and low-fat diets. This is because, when in ketosis, the body burns fat for energy instead of carbohydrates.

However, it is important to note that gram per gram, fat is more calorie-dense than carbohydrates: each gram of fat has 9 calories, while a gram of protein or carbohydrate has 4 calories. This means that, while the body may burn more calories on keto, it also consumes more calories, as the diet is high in fat.

How to Maximise Calorie Burn on Keto

If you are on the keto diet and want to maximise calorie burn, there are a few things you can do:

• Ensure you are in ketosis by testing your blood or urine ketone levels using ketone test strips.
• Focus on low-intensity, steady-state workouts such as jogging, cycling, yoga, or rowing. These types of workouts are less likely to be negatively impacted by the ketogenic diet.
• If you are doing high-intensity workouts, consider a targeted keto approach by consuming an additional 15-30 grams of net carbs from simple carbohydrates (like fruit) 30-60 minutes before your workout. This will give your body the fuel it needs to power through high-intensity exercise.
• Make sure you are eating enough, especially healthy fats such as MCT oil, fresh fish, omega 3, avocado, and quality meats. It is common to overlook micronutrients on the heavily macro-focused keto diet, but these provide your body with important vitamins and minerals.
• Listen to your body and adjust your workout routine, eating habits, and macronutrient ratios accordingly. There is no "one size fits all" template when it comes to keto, so find what works best for you and your body.

Keto is better for maintaining muscle mass than building it

The ketogenic diet is a very low-carb, high-fat diet that encourages your body to use ketones as fuel instead of glucose, which is the body's preferred source of energy. While it is possible to build muscle on a keto diet, it may be better suited for maintaining muscle mass. Here's why:

Keto and Muscle Growth

The keto diet restricts carbs, which are important for muscle growth. Carbs promote the release of insulin, an anabolic hormone that helps shuttle nutrients into cells and creates conditions that drive muscle growth. When carbs are limited, muscle cells' access to sugar, one of the fastest fuel sources for the body, is restricted. This can impair the ability of muscles to function at high intensities for activities lasting longer than 10 seconds. As a result, keto may not be ideal for high-intensity exercises such as weightlifting, sprinting, or high-intensity interval training.

Protein Intake

While protein is essential for building muscle, there is a concern among keto dieters about consuming too much. Excess protein can encourage the body to use gluconeogenesis, a process where amino acids from protein are converted into sugar, potentially disrupting ketone production. Additionally, keto diets are often low in calories, making it challenging to consume enough protein to support significant muscle growth. However, studies have shown that consuming around 1 gram of protein per pound of body weight is generally safe and can help maintain muscle mass while in ketosis.

Calorie Surplus for Muscle Growth

To build muscle effectively, you need to consistently eat more calories than you burn. This can be challenging on a keto diet, especially if you are also focusing on weight loss. Creating a calorie surplus while adhering to the strict macronutrient ratios of keto can be difficult and may require careful planning and monitoring of your diet.

Keto and Endurance Exercises

While keto may not be ideal for high-intensity exercises, it can be beneficial for endurance exercises. Once keto-adapted, endurance athletes tend to burn more fat, allowing them to spare glycogen and improve performance. Additionally, the keto diet's focus on fat and protein intake can help improve endurance and fat-burning capabilities during endurance exercises.

Maintaining Muscle Mass on Keto

Keto can be effective for maintaining muscle mass, especially when combined with resistance training. By providing an adequate amount of protein and calories, you can preserve muscle mass while taking advantage of the other benefits of keto, such as weight loss and improved health markers.

In summary, while it is possible to build muscle on a keto diet, it may be more challenging due to the restricted carb intake and the important role carbs play in muscle growth. However, keto can be an effective tool for maintaining muscle mass, especially for endurance athletes or those looking to improve their body composition through weight loss.

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