Intermittent fasting – can it work for you?

Time to fast?

Intermittent fasting – can it work for you?

Intermittent fasting – can it work for you? 1024 683 Alternative Kitchen

Past studies have shown that intermittent fasting (IF) is safe and very effective, but in general no more effective than other diets. As well, many people find fasting difficult. New research has suggested, however, that the timing of the fast is perhaps the key, and can make all the difference. Can one now approach IF as a realistic, sustainable, and effective method for weight loss?

IF as a weight loss method has been around for quite some time, most popularized in 2012 by BBC broadcast journalist Dr. Michael Mosley’s TV documentary Eat Fast, Live Longer and his book The Fast Diet. Journalist Kate Harrison followed this with her book The 5:2 Diet, which was based on her own experience. Then came Dr. Jason Fung’s 2016 bestseller The Obesity Code.

In The Obesity Code, Fung successfully combines research, his clinical experience, and practical nutrition advice, and also looks at the socio-economic forces contributing to our becoming fat in the first place. He advised that we should eat more fruits and veggies, plenty of fiber, healthy protein and fats, and avoid sugar, refined grains and processed foods, and . . . quit the snacking.

The weight loss part

IF makes sense. The food one eats is broken down by enzymes in the gut and eventually ends up as molecules in the bloodstream. Carbohydrates, especially sugars and refined grains (like white flours and rice) are rapidly broken down into sugar, which the cells use for energy. If the cells don’t use it all, this energy is stored in the fat cells as . . . fat. Sugar can only enter the cells with insulin, a hormone made in the pancreas. Insulin brings sugar into the fat cells and keeps it there.

Between meals, so long as we don’t snack, insulin levels naturally go down and the fat cells then release their stored sugar for use as energy. One loses weight if the insulin levels go down. The simple idea behind IF is to allow insulin levels to go down far enough and for long enough that fat is burned off.

What, intermittent fasting doesn’t have to be hard?

Initial human studies that compared fasting every other day to eating less every day showed that both worked about equally for weight loss, though the fasting days were where most people struggled. These tests illustrated that IF was no better or worse than simply eating less, only more uncomfortable. Recent new research however is suggesting that not all IF approaches are equal, and some may in fact be very reasonable, effective, and sustainable, especially when combined with a nutritious plant-based diet.

Humans have evolved to be in sync with day/night cycles – their circadian rhythm. Our metabolism has adapted to daytime food and nighttime sleep, and nighttime eating has been associated with a higher risk of obesity and diabetes. Based on this understanding researchers from the University of Alabama recently conducted a study with a small group of obese men with prediabetes. They compared a form of intermittent fasting called “early time-restricted feeding” where all meals were fit into an early eight-hour period of the day (7 am to 3 pm), or spread out over 12 hours (between 7 am and 7 pm). Both groups maintained their weight (did not gain or lose) but after five weeks, the eight-hours group had dramatically lower insulin levels and significantly improved insulin sensitivity, as well as significantly lower blood pressure. And the surprising find – the eight-hours group also had significantly decreased appetite. They weren’t starving . . .

In a nutshell, the study found that just changing the timing of meals, by eating earlier in the day and extending the overnight fast, significantly benefited metabolism even in people who didn’t lose a single pound.
Intermittent fasting

How does changing the timing help?

How why does changing the timing of ones meals to allow for fasting make a difference in the body? A detailed review in the New England Journal of Medicine of the science of IF, showed that fasting is evolutionarily embedded within the human physiology, triggering several essential cellular functions. In fact changing from a fed to fasted state does more than help burn calories and lose weight. The researchers analysed dozens of animal and human studies, showing how fasting improves metabolism, lowers blood sugar, and lessens inflammation, which greatly improves a range of health issues from arthritic pain to asthma. It was shown to also clear out toxins and damaged cells, lowering risks of cancer and enhancing brain function. Wow.

Is it as good as it sounds?

“There is evidence to suggest that the circadian rhythm fasting approach, where meals are restricted to an eight to 10-hour period of the daytime, is effective,” confirmed metabolic expert Dr. Deborah Wexler, Director of the Massachusetts General Hospital Diabetes Center and associate professor at Harvard Medical School. She did recommend that one should find an eating approach that works for the individual and is sustainable.

Basically there is scientific evidence suggesting that circadian rhythm fasting, when combined with a healthy diet and lifestyle, can be an effective approach to weight loss, especially for people at risk for diabetes. Let’s just just take note that those with advanced diabetes or who are on medications for diabetes, or who have a history of eating disorders like anorexia and bulimia, and pregnant or breastfeeding women should not attempt intermittent fasting unless under the close supervision of a physician who can monitor them.

Using this information for better health

Avoid sugars and refined grains. Eat plenty of fruit, vegetables, beans, lentils, whole grains, lean proteins, and healthy fats – basically what we know as a sensible, plant-based, Mediterranean-style diet.
Allow the body to burn fat between meals. Don’t snack. Be active throughout the day, and build muscle tone.
And then consider a simple form of intermittent fasting. Limit the hours of the day when one eats, and if possible make it earlier in the day – between 7 am to 3 pm, or even 10 am to 6 pm, but not in the evening before bed.

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  • Effects of intermittent fasting on health, aging, and disease. de Cabo R, Mattonson MP. New England Journal of Medicine, December 2019.
  • Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. JAMA Internal Medicine, May 2017.
  • Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. American Journal of Clinical Nutrition, January 2005.
  • The Obesity Code, by Jason Fung, MD (Greystone Books, 2016).
  • Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Database of Systematic Reviews and Implementation Reports, February 2018.
  • Metabolic Effects of Intermittent Fasting. Annual Review of Nutrition, August 2017.
  • Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metabolism, May 2018.

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