Too few carbs may lead to an earlier death, study suggests

‘You’ve got to cut back on those carbs.’ How often have you heard or read that statement, or some version thereof? Carbohydrates have for decades been branded an ‘enemy’ of weight loss, but recently we’ve seen a more nuanced approach.

That change is probably a good thing, because a new study suggests not getting enough carbohydrates could actually shorten lifespans. Interestingly, that drawn conclusion applies to men, but in women the study found a separate risk.

The study from Japan’s Nagoya University Graduate School of Medicine (NUGSM) points to dangers linked to ‘extreme’ measures with carbohydrates. While that association applies to men, the study found a similar association in women when looking at fats.

The carbohydrate myth

Lowering carb intake has long been associated with weight loss, and the science supports that association. In line with those findings, low-carb diets remain popular and are actively encouraged.

In Australia, that encouragement extends to government agencies. The CSIRO has its own Low-Carb Diet Health Program. The agency points out that the weight loss that can come with a low-carb diet can produce consequential health benefits. These include improved blood glucose control, reduced risk factors for health disease and reduced diabetes medication requirements.

Importantly, though, the CSIRO program emphasises a “nutritionally complete eating plan”, one that is “lower in carbohydrates”. Low carbohydrates does not mean no carbohydrates. And it does not mean extremely low carbohydrates.

It is when the ‘no’ or ‘extremely low’ approach is taken that the phrase ‘nutritionally complete’ is challenged. And that also applies to fats.

Diets that favour extremely low levels of carbohydrate have been linked to a number of adverse health outcomes. These include excessive ketosis and a number of kidney-related conditions.

Complicating matters is defining what ‘low intake’ means. The American Academy of Family Physicians (AAFP) specifies less than 20 per cent of calories from carbohydrates as its measure. However, there is no standardised measure across the medical community.

The study

Using the AAFP’s definition, anything from 20 to 39 per cent carbohydrate intake will not be counted as low. However, the NUGSM study found a higher risk for men getting less than 40 per cent of their calories from carbohydrates.

The study concluded that men in that category had a significantly higher risk of all-cause mortality. Women, however, were at a higher all-cause mortality risk if their carbohydrate intake was more than 65 per cent.

Fat intake was also the focus of the study. It found that men with more than 35 per cent fat intake by calories had an increased cancer and cardiovascular mortality. On the other hand, women consuming more fats – particularly saturated fats – decreased their risk of all-cause and cancer mortality.

Untangling the science

As with most studies, this one acknowledges potentially complicating factors. But it does show some fairly clear trends. Managing those factors at an individual level comes back to a couple of old favourites when talking about diet and health.

First, aim for a ‘balanced diet’. That can mean many things, but the underlying philosophy is that a mix of all food types is important. Excluding one entirely unless there’s a medical requirement to do so can bring its own risks.

Second, seek advice from a trusted health expert when in doubt. In most cases, your local GP will be your ideal first port of call.

Have you been on a low-carb diet? What effects did it have, positive or negative?  Let us know in the comments section below.

Also read: How to embrace ageing positively

Disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.

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