Study under review: Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans.
For decades, studies in diverse animal species have shown that calorie restriction (CR) prolongs lifespan and reduces the development of chronic diseases associated with aging. Figure 1 summarizes this evidence.
The life-extending effects of CR have not been directly demonstrated in humans. However, long-term normal weight CR practitioners have shown similar metabolic characteristics as those of animal models, suggesting that CR could be a viable option to prevent modern chronic diseases, even in the absence of obesity and weight loss. But, there are some downsides to long-term CR: loss of lean mass, reduced immune function, as well as potentially reduced quality of life. The protocol itself may also be difficult to follow for many people. An alternative to constant CR that has shown promising effects in animal models is alternating periods of fasting and feasting. One way to do this is through time-restricted feeding (TRF). However, original research in animal models has suggested that an alternate-day fasting (ADF) protocol, in which feeding is restricted to every other day, might have comparable benefits. Current available studies have mostly tested fasting paradigms in people with obesity or participants with metabolic abnormalities using modified ADF paradigms (with consumption of about 25% of calories on fasting days) or in a non-controlled fashion; and metabolic parameters haven’t been measured extensively. Additionally, there is no data on long-term ADF.
The current study attempted to fill this gap in the literature by performing a short term randomized controlled trial (RCT) of ADF compared to a baseline diet in people without obesity, and a long term analysis of a cohort of participants doing ADF for at least six months.
Calorie restriction has been shown to reduce markers associated with aging in diverse animal models. However, it may have potential downsides such as loss of lean mass, reduced immune function, and reduced quality of life. Alternate-day fasting has shown to be promising in animal models as an alternative to calorie restriction, but no study to date has analyzed the effects of a “true” ADF (100% calorie restriction on fast days) on normal weight participants in the long term, as well as its effects on diverse metabolic parameters.
Other Articles in Issue #61 (November 2019)
Mini: Can exercising help alleviate primary dysmenorrhea?
We summarize the main take-aways from a recent Cochrane review exploring exercise's effects on primary dysmenorrhea.
Cutting through liver fat with citrus
Hesperidin, a compound found in the peels of citrus fruits, has shown promising results in rats for improving fatty liver. This trial put hesperidin to the test in people with nonalcoholic fatty liver disease.
Rate of weight loss and body composition: does “slow and steady” win the race?
More severe energy restriction usually leads to higher amounts of weight loss, but it could also lead to a higher proportion of muscle or bone loss. This study explored the effects of the rate of weight loss in postmenopausal women.
Investigating dairy to improve insulin resistance
This meta-analysis suggests that dairy intake can help curb insulin resistance and shrink waistlines a little. But "dairy" is a pretty wide-ranging category...
Casting a wider net for marine oil’s cardiovascular benefits
We previously covered a major meta-analysis which found that marine-derived omega-3 supplementation didn't have clear cardiovascular benefits. However, three large trials have been released since then. Do they make a difference?
Pro-bono: protein for bone retention
When people say they want to lose weight, they usually mean losing the weight from fat. However, weight loss can also lead to bone loss. This study explored whether high-protein diets can help retain bone.
Mini: Nutrient supplements for mental health disorders
We summarize key takeaways from a recent umbrella review that explored how useful nutrient supplementation is for a variety of mental health issues.