Impact of Ketogenic Diets on Strength Performance in Trained Men and Women

Are There Any Advantages or Disadvantages of Following a Ketogenic Diet On Improvements in Strength?

Overview

What did they test? The researchers compiled the findings from six randomized controlled trials to determine if adhering to a ketogenic diet impacted strength outcomes as measured by a 1 repetition max (RM) squat and/or bench press test in individuals with previous resistance training experience.
What did they find? Participants in the control groups increased 1 RM on bench press by 2.78 kg and 1 RM on the squat by 8.15 kg relative to the ketogenic diet groups, but these values were not significant (p>0.05).
What does it mean for you? Carbohydrate restricted diets have become a popular approach to fat loss. One of the concerns with ketogenic diets has been the potential negative impact on exercise performance due to carbohydrates being an important fuel source during high intensity exercise.
The findings of this study suggest that ketogenic diets do not significantly impact strength gains in trained athletes. However, the slightly larger effect size seen in the control participants suggests that there may be some disadvantage to restricting carbohydrates and it is important to weigh the pros/cons of following a carbohydrate restricted diet if your goal is to optimize strength gains.

What’s the problem?

Purpose

Ketogenic and carbohydrate restricted diets have become a popular weight management approach in recent years. However, there is concern that restricting carbohydrates may hinder exercise performance, particularly in higher intensity exercises that rely on glycolytic energy systems and muscle glycogen stores to meet the high energy demands 1. Previous research has shown mixed effects of carbohydrate restricted diets on exercise performance, with some studies showing lower performance, while most show no difference 2. In addition, no impact of ketogenic diets has been shown on muscle hypertrophy 3.

However, it is currently unclear whether ketogenic diets negatively impact strength performance. Therefore, the purpose of this study is to determine whether adhering to a ketogenic diet negatively impacted strength gains as measured by 1 rep max on the bench press or squat exercise.