Dietary Transitions and Health Outcomes in Four Populations - Systematic Review.
Level 4 - case-series / case-control
Systematic review of historical population-level observational and ecological studies
PubMed 35252289 · doi:10.3389/fnut.2022.748305
What was done
A systematic literature review examined the effects of diet and lifestyle transitions on non-communicable chronic diseases (NCDs). The authors identified 22 populations undergoing nutrition transitions; 11 had sufficient data. Four diverse populations were selected for detailed analysis: Yemenite Jews, Tokelauans, Tanushimaru Japanese, and Maasai. Seven additional populations (Pima, Navajo, Aboriginal Australians, South African Natal Indians and Zulu speakers, Inuit, and Hadza) were reviewed to evaluate bias.
What was found
In three groups where saturated fatty acids (SFA) were replaced with refined carbohydrates, health outcomes worsened: - Yemenite Jews reduced SFA consumption by >40% post-transition, sugar intake increased 600–650%, men's BMI rose 19%, and diabetes increased ~40-fold. - Tokelauans reduced total fat and SFA and increased sugar by 600–650%; obesity and diabetes increased. - Maasai transitioned to lower fat and SFA with higher carbohydrates (total carbohydrates increased 39% in men and 362% in women); BMI and diabetes increased. - Tanushimaruans transitioned to more fat, fewer carbohydrates, and increased antihypertensive medication; stroke and breast cancer declined while heart disease remained stable. Across 11 populations, NCDs were most strongly associated with increases in sugar and refined carbohydrates rather than increased calories, reduced activity, or SFA and total fat intake.
Why it matters
This review synthesizes historical epidemiological shifts to argue that the emergence of obesity and diabetes in transitioning populations correlates primarily with refined carbohydrate and sugar uptake rather than saturated fat consumption.
Limits
The findings rely on historical observational and ecological comparisons with non-standardized dietary assessment methods across different eras. Confounding from concurrent lifestyle changes (e.g., physical activity, healthcare access, smoking, and medication use) cannot be excluded, and causality cannot be determined from population-level transition data.
Cited by
- context Following the adoption of Western diets, 50% of Inuit populations suffer from cancer, dementia, and diabetes.