The individuals who followed the ketogenic diet saw a sizeable spike in fat usage and a decrease in carbohydrate usage during the one-mile workout. On average, fat utilization increased by 190%, while carbohydrate utilization decreased by 20%. The low-carb and high-carb groups showed no variation between the 1-mile and 6 X 800-meter sprint tests. This study challenges the notion that high carbohydrates diets are superior to low-carb diets for improving performance.
KETO WORKOUT PLAN AND DIET FOR EXERCISE SUMMARY
- The individuals who followed the keto workout plan saw a sizeable spike in fat usage and a decrease in carbohydrate usage during the one-mile workout. On average, fat utilization increased by 190%, while carbohydrate utilization decreased by 20%.
- The low-carb and high-carb groups showed no variation between the 1-mile and 6 X 800-meter sprint tests.
- This study challenges the notion that high carbohydrates diets are superior to low-carb diets for improving performance.
LIFTING WEIGHT ON KETO IS NOT DETRIMENTAL
In recent years, high-fat intake, low-carb and ketogenic diets have been advocated as beneficial for losing weight but detrimental to performance (i.e., especially during highly intensive workouts). Many coaches and sports scientists have suggested that weight lifting on keto decreases performance and muscle growth. Many athletes are told to consume a high-carbohydrate diet to enhance recovery after exercise, improve performance, and gain muscle.
Recent studies have questioned the claim that weightlifting on keto workout plans and diets will decrease performance, with bouts lasting less than an hour. Carbohydrate intake per se is unlikely to affect strength training performance in a fed state in exercise routines consisting of up to 10 sets per muscle group. (Henselmans et al., 2022)
THE PROS AND CONS OF KETO DIETS
Ketogenic and alternate versions, such as the keto intermittent fasting diets, have resulted in greater fat loss and short-term weight loss. Still, many people start eating more carbohydrates and gaining long-term weight due to the difficulty of staying on a ketogenic diet. (Hansen et al., 2023) Ketogenic diets result in an increase in fat utilization during exercise. Since the human body has abundant fat cells compared to glycogen stores, this can be advantageous for exercise. (Havemann et al., 2006)
HOW TO ENTER KETOSIS?
When following a low-carb ketogenic diet, your body switches from utilizing carbohydrates as an energy source to fats as an energy source. A ketogenic diet is usually defined as consuming less than 50 grams of carbohydrates per day, and “low-carbohydrate” is usually 50-150 grams daily. (Gomez-Arbelaez et al., 2017; Johnstone et al., 2008)
The process is called “ketosis.” During ketosis, blood ketone levels rise dramatically. Ketones are the breakdown products of fat used to fuel cells that normally depend on glucose. Many people want to know how to get into ketosis fast!
Achieving ketosis by restricting carbohydrates and intense exercise will quickly result in an elevation in blood ketones. (Harvey et al., 2019)
DOES A KETO WORKOUT PLAN DECREASE PERFORMANCE?
Previous research has shown that ketogenic diets result in a decrease in performance. (Burke et al., 2017; Burke et al., 2021) These authors suggested that carbohydrates are needed for short, high-intensity exercise. Part of the reason why ketogenic diets may reduce performance may be due to nutrient deficiencies, as ketogenic diets cause increased electrolyte excretion. (Bostock et al., 2020)
NEW STUDY ON KETO WORKOUT PLANS
A new research study published in Frontier in Medicine questions any decreases in performance following a keto workout plan. The study had 10 trained male athletes, 40 years of age, complete two 31-day dietary interventions separated by a 2-week washout period:
4 Weeks of Low Carb, High Fat (LCHF): < 50 grams of carbohydrates, 15%–20% protein, and 75%–80% fat.
4 Weeks of High Carb, low-fat diet (HCLF): 20% fat, 60%–65% carbohydrate, 15%–20% protein.
Unlike other studies, the researchers had the ketogenic diet phase supplemented with 1-2 grams of sodium per day from bouillon cubes or homemade broth. As mentioned previously, the reason for this is that the ketogenic diet enhances electrolyte excretion. The subjects had blood ketones measured frequently to confirm they were in ketosis. The amount of protein was the same between the diets; the only differences were in fat.
The researchers measured performance (i.e., 1 mile trial time, 6 X 800 meter sprint performance) in conjunction with body composition, glucose, ketones, cardiovascular, and metabolic profiles (i.e., cholesterol, LDL, HDL, etc.).
SHOCKING INCREASES IN FAT METABOLISM ON LOW-CARB DIETS
The finding was a big shocker for the research community. When the subjects were on the ketogenic diet, during the 1-mile exercise, the average fat oxidation increased (+190%), and average carbohydrate oxidation decreased (-20%). During the repeated sprint test, average fat oxidation increased (+92%), and average carbohydrate oxidation decreased (-54%). There was no difference in performance between the LCHF and HCLW diets.