Intermittent Fasting’s Darkest Secret

Summary

Intermittent fasting has gained popularity for weight loss and health, but research reveals it works mainly through calorie restriction, not additional benefits. While animal studies show promise, human studies find similar results to other calorie-restricted diets. There are two fixable issues with intermittent fasting - getting adequate protein intake, and proper meal timing. Overall it can help some people lose weight, but does not provide special benefits over other diets. More research on prolonged fasts is still needed regarding muscle loss.

Takeaways

• 😀 Intermittent fasting can help with weight loss and diabetes treatment, but the benefits come from calorie restriction, not something unique about fasting itself.
• 😞 For healthy people who don't need to lose weight, there are no clear additional benefits from intermittent fasting.
• 👊 For weight loss and diabetes treatment, intermittent fasting works due to calorie reduction.
• 🍴 Protein intake and meal timing are key issues with intermittent fasting that need to be addressed.
• ⌛️ Humans don't fast long enough to activate autophagy like mice do in short-term fasts.
• ⏰ Early time-restricted feeding (eating breakfast, fasting at night) may be optimal intermittent fasting pattern.
• 🥣 Eating breakfast is important; the biggest meal should be earlier in the day, not at night.
• 💪 Prioritize protein intake (1.6 g per kg lean body weight) when fasting to protect muscle.
• 🤝 Prolonged fasting has risks - more research needed to confirm potential benefits outweigh them.
• 😊 For some people, intermittent fasting is an effective weight loss tool, so long as protein and meals are addressed.

Q & A

What is the dark secret about intermittent fasting?

The dark secret is that in humans, intermittent fasting works through calorie restriction alone. There is no evidence that something magical is happening beyond calorie restriction.

Why did intermittent fasting become popular initially?

It became popular due to studies in rodents showing benefits like weight loss, improved blood sugar control, and lowered insulin levels even when the intermittent fasting group ate the same calories as the control group.

What are the two main problems with intermittent fasting?

The two main problems are: 1) Not getting enough protein intake leading to muscle loss 2) Having a large meal late at night which can worsen blood sugar control.

How can the protein intake problem be solved?

The protein intake problem can be solved by prioritizing protein in the diet and adding a protein shake if needed to reach the target intake of 1.6g per kg of body weight.

What should the meal timing be for intermittent fasting?

Most calories should be consumed earlier in the day. A good rule of thumb is to eat breakfast like a king, lunch like a prince, and dinner like a pauper to avoid large nighttime meals.

Why don't humans see the same fasting benefits as rodents?

A 16 hour fast for a mouse is equivalent to a 4-5 day fast for a human. So intermittent fasting of 16-24 hours is unlikely to meaningfully activate autophagy in humans like it does in mice.

Is intermittent fasting more effective for weight loss compared to other diets?

No, research shows intermittent fasting is not more effective for weight loss compared to other calorie restriction diets when calories are matched.

Does intermittent fasting lower hunger?

For most people, no. Some individuals may experience lower hunger but generally fasting does not lower overall hunger levels based on clinical studies.

Are there benefits to prolonged fasting?

There are concerns about muscle loss with prolonged fasts. More research is needed to determine if any potential benefits outweigh these known risks in humans.

Who may benefit from intermittent fasting?

It can be an effective strategy for some people to lose weight and treat conditions like diabetes. But otherwise healthy people are unlikely to see additional benefits beyond calorie restriction.