A new study reveals that severely limiting your intake of carbohydrates and fats could shorten your life

A new study suggests that extreme dietary habits involving low carbohydrate intake in men and high carbohydrate intake in women are associated with higher risks of mortality. A high fat intake in women, however, may reduce the risk of all-cause and cancer mortality, highlighting the need for a balanced diet.

A new study, published inThe journal of nutrition, indicates that extreme dietary patterns related to fats and carbohydrates could impact longevity. The research, led by Dr. Takashi Tamura of Nagoya University Graduate School of Medicine in Japan, reveals that men with low carbohydrate intake and women with high carbohydrate intake face a higher risk of general and cancer-related death. Additionally, the study suggests that women who consume more fat may experience a reduced risk of death from any cause.

Their findings suggest that people should eat a balanced diet rather than severely limiting their intake of carbohydrates or fats.

While low-carb, low-fat diets are becoming popular as a way to promote weight loss and improve blood glucose levels, their long-term effects on life expectancy are less clear. Interestingly, recent studies conducted in Western countries suggest that extreme carbohydrate and fat eating habits are associated with a higher risk of mortality. However, few studies have explored these associations in East Asian populations, including Japanese individuals who typically have relatively low-fat and high-carbohydrate dietary intakes.

The authors conducted a 9-year follow-up survey of 81,333 Japanese (34,893 men and 46,440 women) to evaluate the association between carbohydrate and fat intakes and mortality risk. Daily carbohydrate, fat, and total energy intakes were estimated using a food frequency questionnaire and calculated as a percentage of total energy intake for carbohydrates and fat.

The quality of carbohydrate intake (i.e., refined versus minimally processed carbohydrate intake) and the quality of fat intake (i.e., saturated versus unsaturated) were also evaluated to examine the impact of food quality on association with mortality.

They found that men who consumed less than 40 percent of their total energy from carbohydrates had significantly higher risks of all-cause and cancer-related mortality. The trend was observed regardless of whether they were considered refined or minimally processed carbohydrates. On the other hand, among women with 5 years or more of follow-up, those with a high carbohydrate intake greater than 65% had a higher risk of all-cause mortality. No clear association was observed between the intake of refined or minimally processed carbohydrates and mortality risk in women.

As for fat, men with a high fat intake of more than 35 percent of their total energy from fat had a higher risk of cancer-related mortality. They also found that a low intake of unsaturated fat in men was associated with a higher risk of all-cause and cancer mortality. In contrast, total fat intake and saturated fat intake in women showed an inverse association with the risk of all-cause and cancer-related mortality. They concluded that this finding does not support the idea that high fat intake is detrimental to longevity in women.

The finding that saturated fat intake was inversely associated with mortality risk only in women could explain some of the differences in the associations between the sexes, said Dr. Tamura. Alternatively, non-fat components in dietary fat sources may be responsible for the observed inverse association between fat intake and mortality in women.

This study is extremely important because carbohydrate and fat restriction, such as extremely low-carb and low-fat diets, are popular dietary strategies today aimed at improving health, including management of metabolic syndrome. However, this study shows that low-carb, low-fat diets may not be the healthiest strategy for promoting longevity, as their short-term benefits could potentially be outweighed by long-term risks.

Overall, an unfavorable association with mortality was observed for low carbohydrate intake in men and high carbohydrate intake in women, while high fat intake may be associated with a lower risk of mortality in women. women. The findings suggest that individuals should carefully consider how to balance their diet and ensure they are getting energy from a variety of food sources while avoiding extremes.

Reference: Dietary carbohydrate and fat intake and risk of mortality in the Japanese population: The Japanese multi-institutional collaborative cohort study by Takashi Tamura, Kenji Wakai, Yasufumi Kato, Yudai Tamada, Yoko Kubo, Rieko Okada, Mako Nagayoshi, Asahi Hishida, Nahomi Imaeda, Chiho Goto, Hiroaki Ikezaki, Jun Otonari, Megumi Hara, Keitaro Tanaka, Yohko Nakamura, Miho Kusakabe, Rie Ibusuki, Chihaya Koriyama, Isao Oze, Hidemi Ito and Keitaro Matsuo, June 2, 2023, The journal of nutrition.
DOI: 10.1016/j.tjnut.2023.05.027