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Intermittent Fasting: Dietary Fad or Fact

Dr. Mundi uncovers the truth behind the trending diet fad, intermittent fasting, and how it might actually help you better than the standard calorie reduction recommended by most doctors.
August 18, 2021
Manpreet S. Mundi, M.D.

“There are many diets that patients are continuously asking us about. The first patient I remember who asked about intermittent fasting was a 38-year-old woman who had struggled with weight all of her life.

She had pretty much tried everything: self-administered diets, formal programs. She says, “I'm really thinking about intermittent fasting. What do you think?”

And before this, I think I'd always labeled it as this fad diet. We have a lifestyle, we have medications, and we have all these procedures. But more and more patients are coming to us looking for alternatives. And the first question is why?

THE QUESTION: Why Intermittent Fasting?

We have such good data from big trials that were done through the diabetes prevention program. Why are patients still looking for other options?

Essentially, the diabetes programs were trying to get 7 percent weight loss in an effort to prevent the occurrence of diabetes. So these were all overweight patients who were at risk for developing diabetes. They did 16 lessons over many weeks and then followed them closely.

And they hit their goal. They got 7 percent weight loss by 6 months. But the patient is essentially saying, I'm working my butt off, and you're telling me I'm only going to lose 2 kg? They're saying there's obviously something about the standard calorie reduction approach that's unsustainable.

THE DEMAND: Why is Intermittent Fasting Getting So Popular So Fast?

So my patients wonder, are there better options? And the ones they’re getting bombarded with in the media are things like intermittent fasting.

With intermittent fasting, the message that's being sent to patients is that you have to reduce your eating today by about 500 calories (or 1 meal a day), but tomorrow you get to eat what you want. And the Wolverine is doing it, so it has to be good.

So do you actually get any weight loss? Are there metabolic benefits? And the key: is it sustainable?

That's what these next sets of trials looked at. And they found that intermittent fasting is way more sustainable. We're not really seeing an increase in calorie intake on those Fed days. So they're not making up that reduction the next day by overeating, at least in trials.

THE TEST: Does Intermittent Fasting Actually Work?

Next are those hunger markers. At least with this approach, you're not seeing a worsening in hunger. And the weight loss is tremendous. In those 12 weeks, 6 and a half percent weight loss.

And obviously, as you lose weight, your blood pressure gets better. Cholesterol got better. You're getting all of these metabolic benefits and more.

In our caveman days, when we did almost intermittent fasting, was the brain more prepared to help us find food? Yes. So that's what they're doing here, increasing synaptic plasticity. And there's a lot of work going on in animal models for dementia. Is there some benefit in terms of fasting and Alzheimer's? Are we producing new neurons? That's been shown in the models.

THE CONCLUSION: How to Recommend Intermittent Fasting to Your Patients

With this in mind, I've changed my own strategy, so if a patient comes in, I'm no longer saying that intermittent fasting is this fad diet.

I think if a patient is motivated enough, I will say, well, I will help you with that. The studies show that, typically, a modified fasting regimen is the way to go, but it’s not for everyone. If it’s right for you, eating about 500 calories for lunch on one fasting day is a way to start, if you want. That's OK. We'll start there.”

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