Effects of 12-Week Balanced Diet on Body Composition & Metabolic Parameters in Twins

Background: Twin studies help separate genetic and environmental influences on diet and metabolic health. With rising obesity and metabolic disorders in Pakistan, there is no twin-based dietary intervention data. Filling this gap is essential for developing effective, evidence-based personalized nutrition strategies.

Hypothesis: The null hypothesis states that there will be no difference in dietary response or within-pair similarity between monozygotic and dizygotic twins. The alternative hypothesis suggests that monozygotic twins will show greater similarity in diet response and that the balanced diet will significantly improve metabolic outcomes.

Methodology: A 12-week randomized controlled trial will recruit Monozygotic and Dizygotic twins aged 18-60 years in Lahore, Pakistan. Participants of interventional group will follow a WHO-aligned balanced diet. Body composition, metabolic markers, and dietary adherence will be assessed at baseline and week 12.

Statistical Design: Analyses will be conducted in SPSS using paired t-tests for within-pair comparisons and independent t-tests for Monozygotic vs. Dizygotic differences. Effect sizes will be calculated, with significance set at p < 0.05.

Expected Outcomes: The study is expected to show that the balanced diet improves metabolic and body composition outcomes, with monozygotic twins displaying more similar responses than dizygotic twins. These findings will clarify genetic vs. environmental effects and support more targeted nutrition recommendations in Pakistan.

Inclusion criteria

• Male or female twins aged 18-60 years.
• Confirmed zygosity (MZ or DZ) based on a validated twin zygosity questionnaire.
• Both twins willing to participate for the entire intervention period.
• Free from chronic diseases requiring specialized diets (e.g., type 1 diabetes, celiac disease).
• Not currently enrolled in another dietary or lifestyle intervention study.

Exclusion criteria

• Pregnant or lactating women.
• Use of lipid-lowering, glucose-lowering, or weight-loss medications in the past 3 months.
• Major gastrointestinal disorders or conditions affecting nutrient absorption.
• Unwillingness to follow individualized dietary counseling or complete study assessments.