Show Notes
Intermittent fasting may help with blood sugar, appetite, fat loss, and energy. But many people do it wrong.
In this episode, Professor James Betts, one of the world’s leading experts on meal timing and its metabolic effects, explains what fasting actually is, how long you need to fast to see changes, and the key mistakes that can stop the benefits.
Today, we break down what happens in your body when you stop eating and explain why it may support weight loss and blood sugar control, but also why fasting doesn’t work for everyone. You will learn why breakfast may not matter, why the 5:2 diet often fails, and why eating even small amounts can stop a true fast.
By the end of this episode, you will understand what counts as a real fast, how long your eating window may need to be, why longer is not always better if you cannot stick to it, and why planning your first meal matters, because hunger can drive poor choices.
If fasting can work, but is not magic, what actually makes the difference: the timing, the consistency, or simply eating less?
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Timecodes
Intro
The answers that completely contradict fasting advice
What fasting really means (it’s not what you think)
Why most people never actually fast
Why “eat to fuel your day” may be wrong
The 3 types of fasting people confuse
Why 5:2 might not work the way you think
The tiny mistake that ruins a fast
Why stricter fasting can feel easier
Why hunger disappears after a few days
What happened when he fasted for 5 days
What you can actually have during a fast
Do coffee and tea break your fast?
The truth about breakfast (finally tested)
The breakfast result no one expected
The hidden downside of fasting
What your body switches to when you stop eating
What really happens on day two of fasting
Why fasting might improve your health
Does fasting reduce inflammation?
What fasting actually helps with
How much weight people really lose
The most effective way to fast
The minimum fasting window that works
Who benefits most from fasting
Should you exercise before eating?
Do your eating times need to be consistent?
Does olive oil secretly break a fast?
The one rule for breaking a fast
The biggest takeaway about fasting
Should you actually try fasting?
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Mentioned in today's episode
Effect of the 5:2 Diet on Weight Loss and Cardiovascular Disease Risk, The International Journal of Endocrinology (2025)
Intermittentfasting ‘no magic bullet for weight loss’, Science Translational Medicine (2021)
BathBreakfast Project, Springer (2011)
Therole of intermittent fasting and meal timing in weight management and metabolic health. Proceedings of the Nutrition Society, (2020)
Thecausal role of breakfast in energy balance and health: a randomized controlled trial in lean adults. American Journal of Clinical Nutrition, (2014)
Nutrienttiming and metabolic regulation. The Journal of Physiology, (2022)
Caloriecounting vs. minute counting; does nutrient timing matter for weight-loss? Current Opinion on Clinical Nutrition and Metabolic Care, (2025)
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Episode transcripts are available here.