**Background:** Obesity is a global pandemic affecting over 2 billion adults worldwide, with Mexico facing an alarming prevalence of 75.2% in adults aged 20 years and older (ENSANUT 2018). Mexican ancestral foods—cocoa (Theobroma cacao), nopal (Opuntia ficus-indica), avocado (Persea americana), and common bean (Phaseolus vulgaris)—have been individually studied for their bioactive compounds including flavonoids, polyphenols, dietary fiber, and antioxidants, which may confer health benefits such as glycemic control, cardioprotection, anti-inflammatory effects, and weight management. This systematic review and meta-analysis aimed to evaluate the collective evidence for these foods in modulating anthropometric and biochemical parameters in obese patients.
**Methods:** Two independent researchers conducted a systematic search of PubMed, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) for studies published between 2012 and 2022. From an initial pool of 4664 articles (625 from PubMed, 34 from CENTRAL, 2255 from Web of Science, and 1750 from Scopus), 2017 duplicates were removed, and 2647 records were screened. After full-text review of 118 articles, 15 studies met the inclusion criteria: prospective, randomized, controlled, open or blinded trials enrolling adults (>18 years) with overweight, obesity, diabetes mellitus, or metabolic syndrome, who were prescribed cacao, nopal, avocado, or common bean consumption. Studies reporting at least one outcome (BMI, waist circumference, total cholesterol, triglycerides, HDL-c, LDL-c, glucose, insulin, or HOMA-IR) at baseline and end of intervention were included. Eight studies assessed cocoa/dark chocolate, two studied common bean, three evaluated avocado, and two examined nopal. Study durations ranged from 4 weeks to 6 months. Meta-analysis was performed using Review Manager Version 5.3 with random-effects models, inverse variance method, and 95% confidence intervals. Heterogeneity was assessed using Cochran's Q test and I² statistics.
**Key Results:** The meta-analysis demonstrated a statistically significant reduction in BMI with Mexican ancestral food supplementation compared to control groups: mean difference −0.80 (95% CI: −1.31 to −0.30, p = 0.002), though heterogeneity was considerable (I² = 92%, p < 0.00001). Body weight showed a non-significant reduction (−0.57, 95% CI: −1.93 to 0.79, I² = 54%). Waist circumference also showed a non-significant reduction (−0.16, 95% CI: −2.54 to 2.21, I² = 90%). For lipid parameters, total cholesterol showed a mean difference of −5.04 mg/dL (95% CI: −11.15 to 1.08, I² = 92%), triglycerides −10.11 mg/dL (95% CI: −27.87 to 7.64, I² = 98%), LDL-c −3.47 mg/dL (95% CI: −7.22 to 0.27, I² = 87%), and HDL-c −3.13 mg/dL (95% CI: −6.81 to 0.54, I² = 98%), none reaching statistical significance. For glycemic outcomes, fasting plasma glucose showed a mean difference of −0.81 mg/dL (95% CI: −5.81 to 4.19, I² = 94%), HOMA-IR −0.24 (95% CI: −0.52 to 0.04, I² = 70%), and insulin −0.15 (95% CI: −0.80 to 0.50, I² = 75%), all non-significant. Individual studies reported notable findings: Leyva-Soto et al. (2018) found significant reductions in HOMA-IR (2.4 ± 1.5 vs. 1.93 ± 1.1) and fasting glucose (111.67 ± 10.9 vs. 91.23 ± 9.25 mg/dL) after 6 months of flavonoid-rich chocolate. Wang et al. (2020) reported mean weight loss of 2.24 kg in the common bean extract group vs. 0.29 kg in placebo over 35 days. Lichtenstein et al. (2022) found significant reductions in total cholesterol (19,039 vs. 18,540 mg/dL) and LDL-c (11,434 vs. 11,034 mg/dL) with daily avocado consumption over 6 months in 1008 participants.
**Clinical Implications:** This systematic review provides preliminary evidence that Mexican ancestral foods may serve as beneficial dietary adjuncts for obesity management, particularly for improving BMI. The significant reduction in BMI (−0.80 kg/m²) is clinically meaningful at the population level, though the high heterogeneity (I² = 92%) warrants cautious interpretation. The non-significant trends toward improvement in lipid and glycemic parameters suggest potential metabolic benefits that may require larger, longer-term studies to confirm. The diversity in study designs, doses, food forms (raw, extract, capsules, beverages), and intervention durations (4 weeks to 6 months) contributed to substantial heterogeneity across all outcomes. Notably, 53.3% of studies had unclear risk of bias for random sequence generation and allocation concealment, and 40% had high risk of bias for blinding of participants and personnel due to the difficulty of creating adequate placebos for whole foods. The authors recommend future research with larger sample sizes, standardized dosing protocols, longer intervention periods, and studies evaluating synergistic effects of combined traditional foods.