Higher adherence to the Planetary Health Diet during energy restriction was associated with greater weight loss and improved body composition, with each 10-point increase in adherence increasing odds of achieving ≥10% weight loss by 49%.
Key Findings
Results
Higher Planetary Health Diet (PHD) adherence was associated with lower BMI compared to the lowest-adherence quartile.
Participants in the highest-adherence quartile had lower BMI than those in the lowest-adherence quartile of -0.94 kg/m2 (95% CI: -1.62 to -0.31; p = 0.005)
Higher PHD adherence was also associated with lower waist circumference and body fat percentage
Data were analyzed from 403 adults with overweight or obesity at baseline and at 3 and 6 months
Two controlled dietary interventions prescribing a 30% energy deficit were used
Associations were assessed using mixed models, logistic regression, and mediation analyses
Results
Each 10-point increase in PHD adherence score increased the odds of achieving excellent weight loss (≥10% body weight reduction) by 49%.
OR = 1.49; 95% CI: 1.03–2.16
Excellent weight loss was defined as ≥10% body weight reduction
PHD adherence was quantified using an energy-adjusted score based on EAT-Lancet dietary targets
Logistic regression was used to assess this association
Results
Red and processed meat reduction and higher whole-grain intake mediated the associations between PHD adherence and weight/body composition outcomes.
Mediation analyses identified these two dietary components as key mediators
Red and processed meat reduction was one of the key PHD components examined
Higher whole-grain intake was the other identified mediating component
These findings highlight specific dietary components within the PHD that drive the observed associations
Methods
The study population consisted of 403 adults with overweight or obesity enrolled across two controlled dietary intervention trials.
ClinicalTrials.gov identifiers NCT02737267 and NCT03183193
Both interventions prescribed a 30% energy deficit
Data were collected at baseline and at 3 and 6 months
PHD adherence was quantified using an energy-adjusted score based on EAT-Lancet dietary targets
Background
The contribution of dietary quality, as measured by PHD adherence, to weight-loss and body composition outcomes during hypocaloric interventions was characterized.
Obesity management typically relies on energy restriction, but the role of diet quality during such interventions was previously poorly characterized
The PHD adherence score was based on EAT-Lancet dietary targets and was energy-adjusted
Associations between PHD adherence and outcomes were evaluated across the full intervention period of up to 6 months
What This Means
This research suggests that not just how much you eat, but what you eat, matters for weight loss during a calorie-restricted diet. Researchers followed 403 adults with overweight or obesity through two controlled diet programs that both required eating 30% fewer calories than usual. They measured how closely participants followed the Planetary Health Diet (PHD) — a scientifically developed eating pattern that emphasizes plant-based foods, whole grains, and limits red and processed meat — and tracked changes in weight and body composition over 6 months.
The study found that people who more closely followed the Planetary Health Diet lost more weight and had greater reductions in BMI, waist circumference, and body fat. Specifically, those in the highest adherence group had a BMI that was about 0.94 kg/m² lower than those in the lowest adherence group. For every 10-point improvement in their diet quality score, participants were 49% more likely to achieve the goal of losing at least 10% of their body weight. The two dietary factors that most explained these benefits were eating less red and processed meat and eating more whole grains.
This research suggests that focusing on the quality of food choices — particularly reducing red and processed meat and increasing whole-grain consumption — during a calorie-restricted diet may meaningfully improve weight loss outcomes beyond calorie reduction alone. The findings support the idea that adopting a more plant-forward, environmentally sustainable eating pattern like the Planetary Health Diet could be a practical strategy to enhance the success of weight management programs.
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Mogna-Peláez P, Zhang N, Guasch-Ferré M, Milagro F, Riezu-Boj J, Herrero J, et al.. (2026). Planetary Health Diet Adherence Improves Weight and Body Composition During Energy Restriction.. Obesity (Silver Spring, Md.). https://doi.org/10.1002/oby.70215