Fellas, Low-Carb Diets May Do You More Harm Than Good

Low-carb and high-fat diets like keto have been on everyone’s radar over the past decade or so as a way to lose weight and balance blood glucose levels, but there’s been little research into the long-term effects of such extreme diets. If you’ve been on the low-carb bandwagon lately, it might be time to rethink your diet plan. New research published in The Journal of Nutrition shows that low-carb diets can negatively affect men’s lifespans.

To determine the implications of diets like keto and paleo, Dr. Takashi Tamura and a research team from Nagoya University Graduate School of Medicine in Japan analyzed data from 34,893 Japanese men and 46,440 Japanese women. They completed a follow-up survey nine years later. Participants recorded their food intake in a self-reported questionnaire, and the team calculated the percentage of daily intake for each participant. The team also assessed food quality like saturated versus unsaturated fats and refined versus unrefined carbs.

Dr. Tamura and his team determined that men whose energy intake was comprised of less than 40% carbs of any type, refined, unrefined, or minimally refined, were at higher risk of death from any cause and death from cancer. They also found that men whose energy intake was comprised of more than 35% saturated or unsaturated fat were more likely to die of cancer than those who ate less fat. Men who reported low intake of unsaturated were more likely to die from any cause and cancer than others.

Conversely, in women, those who reported more than 65% of their daily energy intake from carbs were more likely to die from any cause. And, contradicting conventionally held ideas, women who reported high fat intake did not experience a decreased lifespan from any cause.

"The finding that saturated fat intake was inversely associated with the risk of mortality only in women might partially explain the differences in the associations between the sexes," Dr. Tamura said in a statement. "Alternatively, components other than fat in the food sources of fat may be responsible for the observed inverse association between fat intake and mortality in women."

Tamura’s team's findings fly in the face of sources who claim low-carb/high-fat diets are beneficial across the board. While women may find some benefit in decreasing carbs and increasing fats, the findings indicate that men should find a middle ground and not focus too heavily on decreasing one and increasing the other — in other words, eat a healthy and balanced diet above all, without focusing too much on the extremes.

And if adhering to a diet is a lifestyle you prefer, there are plenty that offer such balance. Diets like the Mediterranean Diet, DASH diet, and PURE diet are more balanced alternatives to strict low-carb, high-fat diets that have mountains of research confirming their efficacy in extending lifespans and lowering risks of chronic diseases like cardiovascular disease, diabetes, and cancer. Each of these diets promotes the consumption of healthy fruits and vegetables, whole grains, healthy fats, and lean meat from a variety of sources instead of eschewing certain fruits and vegetables and relying on fats from animal proteins.