Dietary Intake Is Similar Among Adult Men with Different Levels of Cold-Induced Brown Adipose Tissue Activation

Brown adipose tissue (BAT) activation has important metabolic health implications, yet the relationship between habitual dietary intake and BAT activity in humans remains to be fully understood.

We compared dietary intake among adult men with (BAT_positive, age: 34.8 ± 5.4 years, BMI: 28.2 ± 5.3 kg/m², n = 12) and without (BAT_negative, age: 39.1 ± 4.1 years, BMI: 31.1 ± 6.7 kg/m², n = 11) cold-induced BAT activation. Activation of BAT was measured immediately following 2 h of cold exposure using ¹⁸F fluorodeoxyglucose positron emission tomography and computed tomography reported as maximum standardized uptake (SUV_max). Participants categorized as BAT_positive had an SUV_max > 1.5 g/mL that was normalized to lean body mass (SUV_lean) for analysis. Shivering intensity was recorded every 15 min during cold exposure and dietary intake was estimated from 7 consecutive 24 h dietary recalls.

The BAT_negative group was significantly older than the BAT_positive group (p = 0.046). Although BAT_negative participants consumed an average of 281.2 kcal/day more than BAT_positive, there were no significant differences in dietary intake between groups (p ≥ 0.202). Further, no statistically significant associations between SUV_lean and dietary intake among BAT_positive participants were observed (p ≥ 0.175). Participants who shivered (n = 9) during cold exposure tended to be shorter (p = 0.056) and have a lower waist-to-hip ratio (p = 0.097) but did not differ in dietary intake (p ≥ 0.204) or BAT activity (p = 0.964) when compared to the non-shivering (n = 11) group.

Our results indicate that BAT activity and shivering during cold exposure are more strongly related to variables such as age and body size or composition rather than habitual dietary intake. We conclude that habitual dietary intake likely has a negligible influence on BAT activity among adult men.