New Research Says Fasting Beats Cutting Calories – Leonie Heilbronn, Ph.D., with Dave Asprey – #781

Expanded human studies on obesity and chronic disease look at differences in fasting, time restricted eating and calorie restriction.

In this episode of Bulletproof Radio, I’m joined by Australian researcher Leonie Heilbronn, Ph.D.. Her fasting research looks at the biological pathways that support reducing the risk of chronic diseases.

Leonie leads the Obesity and Metabolism group based within the Lifelong Health Theme at South Australian Health and Medical Research Institute at Adelaide University in Adelaide, Australia. Today, I have her on to talk about her studies on fasting, many of which show more specific results than what we’ve seen in this field before. She looks at intermittent fasting, time restricted eating, calorie restriction and more.

In a particular study on women, Leoni says, “We did see that the intermittent fasting group lost a little bit more weight than the caloric restriction group, and they had better improvements in their health.” There were other positive results like reductions in diabetes and cardiovascular risk markers.

Fasting isn’t one-size-fits-all, so I asked Leonie a lot of questions about her research, such as:

  • How does the food you eat during intermittent fasting affect the fast itself?
  • What food works for some people and not others and how does that influence the effectiveness of your fast?
  • How do intermittent fasting and caloric restriction compare?
  • When should you eat your daily protein and carbs?
  • Should you consume black coffee during your fast?
  • How does time-restrictive eating affect your lifespan?

How do people respond in fasting studies? “For some people, it takes them a little while to get used to fasting and then some people just maybe never get used to it,” she says.

How do people respond in time restrictive eating studies? “I think time restrictive eating is great because you don’t really have to change everything that you’re eating and you’re still going to have some really good effects,” she says. “But I think if you started to have bad behaviors because of time pressure, then you’re not going to see the improvement that we’d hope to see.”

Leonie breaks down her research in in simple terms, so no matter what your familiarity with fasting might be, you’ll find a fascinating entry point.

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Follow Along with the Transcript

New Research Says Fasting Beats Cutting Calories – Leonie Heilbronn, Ph.D., with Dave Asprey – #781


Fasting Research by Leonie Heilbronn, Ph.D.:

Key Notes

  • How did you get into fasting? – 1:53
  • Subsequent studies we’ve done have been three days a week of fasting, and not doing alternate day. – 6:04
  • They didn’t see any difference between the calorie restriction and intermittent fasting groups. So I think that intermittent fasting really works for some individuals, but it doesn’t perhaps work for all individuals.  – 9:36
  • If you get inflammation from a nightshade vegetable because of your genetics, you’re going to have a craving, but the next person who doesn’t have those genetics eats them and they’re just fine.   – 12:42
  • Our second trial we’re allowing a eating period of 8:00 AM till lunchtime and then fasting for the rest of the day. – 16:08
  • How are you measuring health outcomes in the study?  – 20:00
  • We’ve seen that fasting or time restricted eating in this case, increase in NAMPT, which is an enzyme that makes NAD. – 22:44
  • Science never works out as you plan it exactly, but so we did see that the intermittent fasting group lost a little bit more weight than the caloric restriction group, and they had better improvements in their health.   – 26:53
  • Have you ever looked at ketone levels directly during any of these?  – 31:21
  • When you’re fasting or when you restrict amino acids, you activate or you inhibit mTOR and you activate autophagy and autophagy goes around and it chews up all of the broken bits in your cells and it makes energy out of them. – 36:40
  • Leonie:
    they see responders and non-responders with Metformin in diabetes all the time. So there’s people that just really don’t respond. – 39:51
  • Any ideas on how important coffee is during a fast?  – 43:27
  • We looked at the continuous glucose monitors at baseline, they were kind of just all over the place here. Whereas if you did time restricted eating, you really bought a 24 hour cycle back into glucose, so that you had low glucose levels at night and higher glucose levels in the day. And that’s probably what we’re supposed to have.   – 47:55

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