Saturday, 1 September 2012

Dr. Krista Varady Interviewed on Alternate Day Fasting

Dr Krista Varady
reposted from:
April 7, 2010 Written by JP - The Health Fellow
crabsallover highlightskey pointscomments / links.

Krista Varady research into Alternate Day Fasting (ADF) is at the very early stages with low trial numbers. Further research is needed using much larger RCTs. The theory is that ADF mimics our hunter-gatherer evolutionary past when feasting was followed by periods of famine. 

JP: Is it fair to say that you believe that the actual practice of prolonged fasting may impart added benefits beyond that of just reducing calories on alternate days?
Dr. Varady: That’s another study I want to design to see if we actually see different effects if we compare people on alternate day fasts that are consuming their meals within that amount of time (12:00 – 2:00) compared to people that are allowed to eat throughout the day. I think that if we did do that study, we’d actually see better effects from people doing the confined eating period. I think our bodies are used to that from the hunter-gatherer days where we’d have days of plenty where we could eat a bunch and then all of a sudden there was nothing out there and we’d have to fast. So I think our bodies are capable of doing that.

JP: How long does it generally take for people to adapt to this new way of eating?
Dr. Varady: A lot of the subjects were saying that for the first two weeks it was pretty tough to basically change from a 3 meal a day eating pattern to just eating 1 meal a day and then 3 slightly bigger meals the next day. But they said that about after two weeks they totally got used to it and weren’t that hungry on the fast day anymore. They could undergo these really long periods of fasting without really feeling deprived. The other interesting thing that they were telling us was with regard to the feed day. The people didn’t binge. They only ate about 100% to 110% of their calorie needs.


The ability of alternate-day fasting (ADF) to modulate adipocyte parameters in a way that is protective against coronary heart disease (CHD) has yet to be tested. Accordingly, we examined the effects of ADF on adipokine profile, body composition, and CHD risk indicators in obese adults. Sixteen obese subjects (12 women/4 men) participated in a 10-week trial with three consecutive dietary intervention phases: (i) 2-week baseline control phase, (ii) 4-week ADF controlled feeding phase, and (iii) 4-week ADF self-selected feeding phase. After 8 weeks of treatment, body weight
and waist circumference were reduced (P < 0.05) by 5.7 ± 0.9 kg, and 4.0 ± 0.9 cm, respectively. Fat mass decreased (P < 0.05) by 5.4 ± 0.8 kg, whereas fat-free mass did not change. Plasma adiponectin was augmented (P < 0.05) by 30% from baseline. Leptin and resistin concentrations were reduced (P < 0.05) by 21 and 23%, respectively, post‑treatment. Low-density lipoprotein cholesterol (LDL-C) and triacylglycerol concentrations were 25% and 32% lower (P < 0.05), respectively, after 8 weeks of ADF. High-density lipoprotein cholesterol (HDL-C), C-reactive protein, and homocysteine concentrations did not change. Decreases in LDL-C were related to increased adiponectin (r = −0.61, P = 0.01) and reduced waist circumference (r = 0.39, P = 0.04). Lower triacylglycerol concentrations were associated with augmented adiponectin (r = −0.39, P = 0.04) and reduced leptin concentrations (r = 0.45, P = 0.03) post-treatment. These findings suggest that adipose tissue parameters may play an important role in mediating the cardioprotective effects of ADF in obese humans. - Interview 2 by Healthy Fellow

JP: I’m fascinated with the role that blood sugar control and insulin sensitivity play in various aspects of health. Does ADF have any significant impact on how the body manages blood sugar and insulin levels?
Dr. Varady: Beyond the weight loss, fasting might play a role in that. You’re not having food come into your body. Therefore you’re not having insulin released by your pancreas. So really you’re having this time where there shouldn’t be much insulin circulating around in your body, which is a good thing because insulin is lipogenic. So it basically causes your fat to be stored and not broken down. It also interacts with certain growth hormones – IGF (insulin-like growth factor) for one, which is related to growth hormone. And that can actually stimulate cell proliferation. So insulin does play a role potentially in cancer risk.

JP: Many people are interested in learning about natural ways of slowing down the aging process. Is ADF a good candidate in this arena?
Dr. Varady: If you have a diet that will slow the rate of cell turnover that’s actually slowing aging technically. I think there’s definitely going to be more data coming out regarding that. I guess after we do most of these weight loss and heart disease efficacy trials, I’d also be interested at looking at the aging process as well

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