Association between the FTO rs9939609 single nucleotide polymorphism and dietary adherence during a 2-year caloric restriction intervention: Exploratory analyses from CALERIE™ phase 2

Effect of FTO genotype on exercise training and diet-indued weight loss in overweight and obese adults: a systematic review and meta-analysis

Our meta-analysis, encompassing 30 studies with 46,976 subjects, aimed to explore the impact of fat mass and obesity-associated protein (FTO) genotypes on weight response to exercise and dietary interventions in overweight and obese adults. Electronic databases including PubMed and Google Scholar were searched from 2020 to September 2023 to identify relevant studies. Results revealed a significant reduction in body weight among individuals with the FTO risk allele following exercise and diet interventions (standardized mean difference [SMD] = - 0.619, 95% CI: - 1.137, - 0.100; p = .01). When examining FTO variants, both AA (SMD = - 0.148, 95% CI: - 0.282, - 0.014, p = .03, I2 = 24.96) and TA genotypes (SMD = - 0.674, 95% CI: - 1.162, - 0.186, p = .007, I2 = 91.12) showed significant weight reduction compared to the TT genotype. Moreover, individuals with the high-risk genotype AA + TT achieved greater weight loss compared to those with the normal-risk genotype TT (SMD = - 0.419, 95% CI: - 0.655, -0.183, p = .0001, I2 = 92.08) in the dominant genetic model. Subgroup analysis indicated that FTO risk allele carriers (AA + AT) with exercise interventions lasting six months and a body mass index of 25 - 29 experienced greater weight loss compared to TT carriers. These findings emphasize the importance of genetic considerations in weight management interventions and suggest personalized approaches for combating obesity. Further clinical trials are warranted to validate our study's findings.

Efficacy of a Comprehensive Weight Reduction Intervention in Male Adolescents With Different FTO Genotypes

BACKGROUND

The FTO gene polymorphisms may influence the effects of lifestyle interventions on obesity. The present study aimed to assess the influence of the rs9930506 FTO gene polymorphism on the success of a comprehensive weight loss intervention in male adolescents with overweight and obesity.

METHODS

This study was carried out on 96 adolescent boys with overweight and obesity who were randomly assigned to the intervention (n = 53) and control (n = 43) groups. The blood samples of the participants were collected, and the FTO gene was genotyped for the rs9930506 polymorphism. A comprehensive lifestyle intervention including changes in diet and physical activity was performed for 8 weeks in the intervention group.

RESULTS

Following the lifestyle intervention, BMI and fat mass decreased significantly in the intervention group compared with the control group (both p < 0.05), while no change was found in weight, height or body muscle percentage between the groups. The participants in the intervention group with the AA/AG genotype and not in carriers of the GG genotype had a significantly higher reduction in BMI (-1.21 vs. 1.87 kg/m2, F = 4.07, p < 0.05) compared with the control group.

CONCLUSION

The intervention in individuals with the AA/AG genotype has been significantly effective in weight loss compared with the control group. The intervention had no association effect on anthropometric indices in adolescents with the GG genotype of the FTO rs9930506 polymorphism.

TRIAL REGISTRATION

Name of the registry: National Nutrition and Food Technology Research Institute; Trial registration number: IRCT2016020925699N2; Date of registration: 24/04/2016; URL of trial registry record: https://www.irct.ir/trial/21447.

Ramadan Diurnal Intermittent Fasting Is Associated With Attenuated FTO Gene Expression in Subjects With Overweight and Obesity: A Prospective Cohort Study

Aim and Background

A growing body of evidence supports the impact of intermittent fasting (IF) on normalizing body weight and that the interaction between body genes and environmental factors shapes human susceptibility to developing obesity. FTO gene is one of these genes with metabolic effects related to energy metabolism and body fat deposition. This research examined the changes in FTO gene expression upon Ramadan intermittent fasting (RIF) in a group of metabolically healthy subjects with overweight and obesity.

Methods

Sixty-three (63) subjects were recruited, of which 57 (17 males and 40 females, mean age 38.4 ± 11.2 years) subjects with overweight and obesity (BMI = 29.89 ± 5.02 kg/m2were recruited and monitored before and at the end of Ramadan month), and 6 healthy subjects with normal BMI (21.4 ± 2.20 kg/m2) recruited only to standardize the reference for normal levels of FTO gene expression. In the two-time points, anthropometric, biochemical, and dietary assessments were undertaken, and FTO gene expression tests were performed using RNA extracted from the whole blood sample.

Results

In contrast to normal BMI subjects, the relative gene expressions in overweight/obese were significantly decreased at the end of Ramadan (-32.30%, 95% CI-0.052 -0.981) in comparison with the pre-fasting state. Significant reductions were found in body weight, BMI, fat mass, body fat percent, hip circumference, LDL, IL-6, TNF-α (P<0.001), and in waist circumference (P<0.05), whilst HDL and IL-10 significantly increased (P<0.001) at the end of Ramadan in comparison with the pre-fasting levels. Binary logistic regression analysis for genetic expressions showed no significant association between high-energy intake, waist circumference, or obesity and FTO gene expression.

Conclusions

RIF is associated with the downregulation of the FTO gene expression in subjects with obesity, and this may explain, at least in part, its favorable metabolic effects. Hence, RIF presumably may entail a protective impact against body weight gain and its adverse metabolic-related derangements in subjects with obesity.