Which Matters Most: Calories, Carbs, or Consumption Patterns?

It’s a familiar debate. Is energy balance governed by physiology, thermodynamics, and calories? Or does dietary quality – perhaps an excess of refined carbs – tell you more? It’s possible that this tired debate is missing an important point. Recent research suggests that consumption patterns might be at least equally important. When you eat and especially periods of fasting might play an important role in health outcomes.

A Noteworthy Study of Longevity in Mice

In Cell Metabolism, Sarah Mitchell and colleagues looked at the importance of diet composition and daily fasting. They compared three different feeding patterns. One was continuous. The mice could eat throughout the day. Then there was a group that received just one meal per day. Food was available for 13 hours and they fasted for 11. The final group had food available for only three hours per day. The researchers controlled for both diet composition and calories consumed.

What they found was a striking relationship between the duration of fasting and longevity. Longer daily fasts resulted in longer survival and better health. And these effects seemed to be independent of both calories and dietary composition.

The authors concluded that these consumption patterns – with longer fasts – may be just as important as dietary quality for health and longevity.

Much More to Learn

Of course, this definitely won’t be the final word. It’s a long way to take these results from mice to humans. And for that matter, these were just male mice.

Even so, researchers are gathering a lot of insight into the effects of intermittent fasting in humans. We know intermittent fasting can be helpful for weight loss and for improving some measures of cardiometabolic health. But it will take longer, well-controlled studies to get a clearer picture of effects on health outcomes.

At the other extreme, we know that grazing all day long is not a very healthy feeding pattern. It’s very common in folks with eating disorders and obesity. Treatment outcomes for obesity are poorer in people who graze – especially after bariatric surgery.

The Wrong Debate?

So all the debates about energy balance and dietary composition might be quite misleading. Time patterns for eating are clearly important for metabolic health, and perhaps for long-term outcomes, too. The findings from Mitchell et al suggest these patterns might be every bit as important as those other two factors. Without considering times of fasting and eating, we may have an incomplete understanding of what makes a healthy dietary pattern.

Click here for the study by Mitchell et al.

Grazing, photograph © Part-time Lion / flickr

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October 4, 2018