In lean adults, morning fasting directly affects the molecular response of abdominal adipose tissue, increasing the expression of genes involved in insulin signaling and lipid turnover compared with those who consume breakfast daily, according to study findings reported in the Journal of Physiology.
“By better understanding how fat responds to what and when we eat, we can more precisely target those mechanisms,” Javier T. Gonzalez, PhD, of the department of health at the University of Bath, United Kingdom, said in a press release. “We may be able to uncover new ways to prevent the negative consequences of having a large amount of body fat, even if we cannot get rid of it.”
Gonzalez and colleagues analyzed data from 29 healthy and lean adults and 19 adults with obesity who underwent subcutaneous abdominal adipose tissue biopsies at baseline and 6 weeks. Participants were assigned to a regimen of either fasting until noon or daily breakfast consumption (350 kcal within 2 hours of waking and at least 700 kcal before 11 a.m.). Researchers measured metabolism, body composition, appetite responses and markers of metabolic and CV health, and analyzed mRNA levels of 44 selected genes and proteins, in addition to GLUT4 and protein kinase B content.
Researchers found that, in lean adults, lipid turnover genes (ACADA, ACADM, LPL) were upregulated when in the fasting state vs. after consuming breakfast. The mean difference of the fast vs. breakfast before and after intervention effect size was 0.5 (95% CI, 0.02-0.99), 0.61 (95% CI, 0.18-1.05) and 0.52 (95% CI, 0.09-0.95, respectively. There were no changes observed in adults with obesity.
In both lean and obese adults, neither fasting nor breakfast consumption effected GLUT4, protein kinase B content and insulin-stimulated protein kinase B phosphorylation.
“Therefore, any potential changes in adipose tissue glucose control with alterations in morning feeding patterns are likely due to proteins involved in signaling and GLUT4 translocation downstream of [protein kinase B],” the researchers wrote.
Researchers also observed that adipose tissue from adults with obesity displays lower rates of insulin-stimulated glucose uptake than that from lean individuals, and that this finding was proportional to whole-body fat mass and may represent an adaptive physiologic downregulation of adipose tissue glucose uptake in obesity.
“Since participants ate high-carb breakfasts, we cannot necessarily extrapolate our findings to other types of breakfasts, particularly those with high protein content,” Gonzalez said in the release. “Our future studies will explore how breakfast interacts with other lifestyle factors, such as exercise.” – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.