Science of exercise, mitochondrial health and longevity | Biochemist Kieron Rooney

Keto & Mitochondria

The ketogenic diet's impact on mitochondrial health is a topic of debate. Drew Harrisberg shares his experience, noting initial improvements in blood glucose and insulin sensitivity, but warns of potential long-term issues like increased fasting glucose and insulin needs 1. He suggests cycling in and out of ketosis while maintaining a whole-food-based diet to avoid negative effects 2. Dr. Kieron Rooney adds that while some individuals report success with long-term keto, comprehensive studies are lacking 3.

If you're sitting in that well going, I'm going to cycle in and out of it and have periods of time where I'm very low carb versus moderate carb. But those carbs are still coming from a healthy food source, then you can't. It'd be really hard to say that's negative.

--- Dr. Kieron Rooney

This approach may help balance the benefits and drawbacks of the diet.

   

Performance Limits

A ketogenic diet may limit performance in high-intensity sports. Dr. Kieron Rooney explains that while keto can support endurance, it may hinder high power outputs due to a mismatch in fuel systems 4. Studies indicate that keto-adapted individuals might struggle with oxygen efficiency at maximum exertion levels 5. Rooney also discusses glycogen levels, noting that long-term keto may not sustain glycogen stores as effectively as carb-rich diets 6.

You might see an advantage up until that 70%, 80% vo, two max value. But then when you push yourself above that, that machinery isn't there.

--- Dr. Kieron Rooney

This suggests that keto might not be ideal for athletes requiring high-intensity bursts.

   

Long-term Health

The long-term health implications of a ketogenic diet are complex. Drew Harrisberg found that prolonged keto use led to decreased glucose tolerance and metabolic flexibility, particularly for those with type 1 diabetes 7. Dr. Kieron Rooney notes that while keto can offer short-term benefits, the lack of long-term data makes it difficult to endorse for extended periods 8. He highlights that initial improvements in health may stem more from eliminating processed foods than from carb restriction alone.

The biggest benefit is potentially from what you eliminated.

--- Dr. Kieron Rooney

This underscores the importance of a balanced, whole-food diet for sustainable health.