The Three Bears

Looking for a Sweet Spot for Carbs

We don’t recommend learning nutrition from headlines. However, if you did, you might certainly think that we can live better without eating sugar. For that matter, why just stop with cutting sugar? Healthline offers you 15 ways to cut carbs for major health benefits. But now, some very clickable headlines are telling us that cutting carbs could shorten your life. Could it be that the truth might offer us a sweet spot for carbs somewhere in between these extremes?

Not Essential But Necessary

One of our thoughtful readers recently suggested that we can live without sugar. In relative terms it is certainly true that we can live with much less of it. And public health crusaders are working to drum added sugar out of the food supply.

Looking beyond sugar, carbs are technically “not an essential nutrient,” say Andre Mente and Salim Yusuf in a Lancet Public Health commentary. But ask anyone who’s tried to live on a very low-carb diet. It’s tough. In a two-year study, the dropout rate was nearly half – 42%.

Carbs and MortalityPrompting that commentary, researchers published a study in Lancet Public Health to suggest that indeed, they’ve found the sweet spot for carbs. Eat less or more than this and your life will likely be shorter, they say.

They provide us with a tidy u-shaped curve to suggest that if you get half of your energy from carbs, you’re at the sweet spot. It’s based on a prospective cohort study and self-reported dietary behavior.

For good measure, the authors throw in a meta-analysis of data from other studies and claim that all these data point to the same answer – theirs.

Inconvenient Limitations

In their commentary, Mente and Yusuf advise caution:

Such differences in risk associated with extreme differences in intake of a nutrient are plausible, but observational studies cannot completely exclude residual confounders when the apparent differences are so modest.

The findings of the meta-analysis should be interpreted with caution, given that so-called group thinking can lead to biases in what is published from observational studies, and the use of analytical approaches to produce findings that fit in with current thinking.

On top of that, all of these conclusions rely upon self-reported dietary data. Some scientists will argue it’s close enough. Others will argue it’s rubbish.

In any event, we would advise you to take all of these claims with a grain of salt. Taken broadly, the idea of a sweet spot for carbs is reasonable. Overdoing it with either restriction or indulgence is seldom a good idea. But it’s unlikely that your life depends on finding precisely where the sweet spot lies. Individual outcomes will surely vary.

Click here for reporting from BBC, here for the study, and here for the commentary.

The Three Bears, illustration by Arthur Rackham / Wikimedia Commons

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August 19, 2018