Does Intermittent Fasting Work? Rehan Jalali: Everything Works Once

You moved breakfast to noon, or dropped it. The scale moved in the first weeks and you told people about it. Then it stopped. Now you are tired by mid-afternoon, softer than when you started, and not sure what you lost.

So does intermittent fasting work, or did it only look like it worked? On the August 6, 2025 episode of Live Well and Thrive, Mike Torchia put the question to Rehan Jalali, whom he introduced as a certified fitness and nutrition expert and the author of The Six Pack Diet Plan. Jalali says he has been in this field for 30 years and that he reads his clients’ blood work. Mike says he does not fast. Between them they gave an answer in two parts: yes, once, and the scale is not telling you what came off.

The wider conversation, personalization, blood work, and how actors prepare for a role, is covered in the post on what a sports nutritionist does. This post stays on fasting. Everything below is two men describing what they have seen in their own clients and what they do themselves. None of it is a prescription.

Does intermittent fasting work? Once, in Jalali’s telling

Jalali did not argue that fasting fails. His claim is narrower than that, and harder to wave off.

Everything works once. I could put somebody on keto, I could put somebody on fasting, and they’ll lose weight.

His point is that the first result proves very little. In his experience, any sharp change in how you eat will move the scale the first time you try it. That is why the person who started last month is always the most convinced. It is also why the question “does intermittent fasting work” gets a yes from nearly everyone who has tried it for a few weeks.

The questions Jalali asks come later. What kind of weight left? Does it stay gone? He told Mike he has kept clients for 15 or 20 years, and that the ones whose results held are the ones who got there slowly. He does not believe in gimmicks or quick fixes, he said, and he puts a fast run for months on end in that category.

The weight that leaves first is muscle and water, Jalali says

Ask Jalali what kind of weight comes off on a fast or a strict diet and his answer is short. Generally it is muscle, or it is water. It is not the kind of weight you wanted to lose, which is fat.

So does intermittent fasting cause muscle loss? From what Jalali says he has watched in his own clients, yes, when it is done continuously. He told Mike he knows men who fasted for a year straight and lost their muscle along the way. They weighed less. They were not leaner in the way they had hoped.

That is the trap in the number. The scale cannot tell muscle and water from fat. A lower reading may be reporting that you lost the tissue you most wanted to keep. Mike does not weigh himself at all, for a related reason: he says weight shifts with water retention, so he goes by the mirror.

Weight that leaves that way tends to come back, in Jalali’s account, and then the cycle repeats. He has a name for it.

If you have that yo-yo effect, you can actually cause more damage to your body than good over the long haul.

He said research backs him on that. He did not name the research on the show, so take it as his reading, not as a citation.

What both men say they saw on fasting clients’ blood panels

Mike raised the subject first, and his concern is duration.

I understand intermittent fasting could be used as a tool, granted, but I know people that have been doing it for three years.

The people he described do not eat three days a week, and they have kept that up for years. Mike says he warned them, and that they now have thyroid issues. His explanation, which is his view and not a lab result quoted on the show, is that long stretches without food suppress the thyroid, the body produces more reverse T3, and the metabolism slows. He told them they had set themselves up to gain fat, and to end up on thyroid medication.

Jalali’s version comes from paper. He says he runs blood work on his clients regularly and looks at the panel before he forms an opinion. In people who had been fasting continuously, he said, he could see it after even three to four months: thyroid markers down, T4 and T3, and in many cases lower testosterone. In the clients who had gone a full year he described muscle gone, thyroid issues, and cortisol running very high.

Those are the intermittent fasting side effects these two men report. They are observations from their own clients and the people around them, not findings from a trial, and neither man said fasting does this to everyone. What your own panel shows is a question for your physician and a lab.

Jalali still fasts, and he counts it in days per year

Is fasting good for you? Jalali’s answer is not a no. He uses it himself.

It’s a tool you can use intermittently. Intermittent is in the word.

His own practice is a three-day fast once a year. He gave his reasons for it on the show; they are his, and this post does not repeat them as claims. He allowed that fasting one day a week may work, and he said it with no more enthusiasm than that. The rest of his guidance was three phrases: use it as needed, use it sparingly, use it when you need to use it.

What he objects to is the word continuously. A tool turns into a lifestyle, the months stack up, and the panel starts to change. Mike agreed with the word tool. Neither man told anyone to stop. Both said the dose is the issue, and that the people who get into trouble are the ones who never put the tool down.

Mike’s alternative is arithmetic and more time

Mike says he does not fast and does not want to. Part of the reason is plain. He is Italian, he said, and he loves to eat. The rest is math. Reduce your calories by a set amount over 72 hours, he said, and the week takes care of itself.

By the end of the week you could lose a pound and a half, two pounds. It’s just a mathematical formula.

So instead of a day with no food, he does a little more cardio, or takes in fewer calories or carbohydrates. He did not give a calorie figure on the episode, and this post will not supply one.

On how to lose fat without losing muscle, what Mike offered is his own routine. Fuel the body, then lift two hours later. Protein, fat, and carbohydrate before and after training, with green vegetables. Care with high-carb food at night. He says that is how he trained for his titles, with no starving involved. He never liked fasted cardio either; where the cardio goes is covered in cardio before or after weights.

The other half of his alternative is time. Mike’s comparison is the Titanic. It could have missed the iceberg, he said, if it had known in time to turn. What he asks of a client is the same thing: enough time to steer, so that nobody has to starve, deprive themselves of food, or do anything extreme to arrive. In his view, the shortcut is what causes the trouble later in life.

How this fits the way Operation Fitness works

Neither man’s objection is to the fast. It is to the guess: a rule borrowed from someone else, run for months, and never checked. Jalali checks it against a blood panel. Mike calls himself the architect, not the handyman, the person who designs the whole structure before anyone picks up a tool. The phrase for that method here is tested, not guessed. Every program is designed by Mike and delivered by his team, and it starts with an assessment of your body. So the honest answer to does intermittent fasting work is that it depends on whose body, for how long, and what the testing shows. The programs page shows how the tiers are built.

Where to go from here

Watch the full episode with Rehan Jalali on YouTube. See how a program here is built from an assessment instead of a trend on the programs page. If the scale has stalled and you want to talk through what you are actually losing, book a consultation.