New Study Reveals That Heavily Restricting Carbohydrate and Fat Consumption Could Be Shortening Your Life

Fresh Study Uncovers Potential Link Between Severe Carbohydrate and Fat Restriction and Reduced Lifespan

Emerging research proposes that adopting extreme dietary patterns, characterized by minimal carbohydrate intake among men and elevated carbohydrate consumption among women, could be associated with heightened mortality risks. Conversely, an increased intake of fats among women might potentially lower the overall risk of mortality, particularly cancer-related mortality. These findings underscore the importance of maintaining a balanced and well-rounded diet.

Recently published in The Journal of Nutrition, a comprehensive investigation helmed by Dr. Takashi Tamura of Nagoya University Graduate School of Medicine in Japan, indicates that radical dietary behaviors focused on carbohydrate and fat consumption might exert significant effects on longevity. Notably, men with a substantially low carbohydrate intake and women with notably high carbohydrate intake seem to confront escalated risks of both general and cancer-linked mortality. Intriguingly, the study also implies that women who incorporate higher fat content into their diets could potentially experience a diminished risk of mortality across various causes.

These revelations strongly suggest the prudence of advocating for a diet that maintains equilibrium between carbohydrate and fat intake, rather than imposing drastic restrictions on either.

While low-carbohydrate and low-fat diets have garnered popularity as means to facilitate weight loss and ameliorate blood glucose levels, their potential long-term impact on life expectancy remains a subject of ambiguity. Strikingly, recent studies carried out in Western nations suggest a connection between extreme dietary habits, encompassing carbohydrates and fats, and an elevated mortality risk. However, few inquiries have delved into these correlations within East Asian populations, such as the Japanese demographic, which traditionally exhibits relatively low fat intake coupled with elevated carbohydrate consumption.

The research team conducted a meticulous follow-up survey spanning 9 years, involving 81,333 Japanese individuals (34,893 men and 46,440 women), to discern the potential links between carbohydrate and fat intake and the susceptibility to mortality. A food frequency questionnaire facilitated the estimation of daily dietary consumption of carbohydrates, fats, and overall energy, quantified as a percentage of total energy intake allocated to these nutritional components.

Moreover, the quality of carbohydrate and fat intake was evaluated—distinguishing refined from minimally processed carbohydrates and saturated from unsaturated fats. This allowed for an assessment of how food quality might influence the mortality association.

The study’s outcomes indicate that men consuming less than 40% of their total energy from carbohydrates faced considerably elevated risks of both all-cause and cancer-related mortality. This trend persisted irrespective of whether refined or minimally processed carbohydrates were analyzed. Conversely, for women with a follow-up period extending beyond 5 years, a carbohydrate intake exceeding 65% was associated with an increased risk of all-cause mortality. However, discerning a clear link between refined or minimally processed carbohydrate intake and mortality risk in women proved elusive.

Concerning fats, men whose diets encompassed over 35% of total energy from fats exhibited an augmented risk of cancer-linked mortality. Notably, a low intake of unsaturated fats in men correlated with amplified risks of both overall and cancer-related mortality. In contrast, in women, total fat intake and saturated fat intake demonstrated an inverse relationship with the susceptibility to all-cause and cancer-related mortality. These findings imply that the notion of high fat intake being detrimental to women’s longevity finds limited support.

Dr. Tamura offered insights into this gender-based contrast: “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.” He further posited that constituents beyond fats in the dietary fat sources might contribute to the observed inverse relationship between fat intake and mortality in women.

This study assumes paramount significance as the practice of restricting carbohydrates and fats—via exceedingly low-carbohydrate and low-fat diets—has gained traction as a strategy to enhance health, including the management of metabolic syndrome. Nonetheless, this investigation underscores that such approaches might not be conducive to fostering longevity, as their short-term benefits could conceivably be outweighed by long-term hazards.

In summation, an unfavorable link with mortality emerges for men curtailing carbohydrate intake and women embracing high carbohydrate intake, whereas an elevated fat intake could potentially correspond to reduced mortality risk in women. Consequently, these findings underscore the necessity of a conscientiously balanced diet that draws energy from an assorted range of food sources, steering clear of extreme nutritional tendencies.

Reference: “Dietary Carbohydrate and Fat Intakes and Risk of Mortality in the Japanese Population: the Japan 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, 2 June 2023, The Journal of Nutrition.
DOI: 10.1016/j.tjnut.2023.05.027

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• The Journal of Nutrition: Link
• Nagoya University Graduate School of Medicine: Link