The causal role of breakfast in energy balance and health: a randomized controlled trial in lean adults

Background: Popular beliefs that breakfast is the most important meal of the day are grounded in cross-sectional observations that link breakfast to health, the causal nature of which remains to be explored under real-life conditions. Objective: The aim was to conduct a randomized controlled trial examining causal links between breakfast habits and all components of energy balance in free-living humans. Design: The Bath Breakfast Project is a randomized controlled trial with repeated-measures at baseline and follow-up in a cohort in southwest England aged 21–60 y with dual-energy X-ray absorptiometry–derived fat mass indexes #11 kg/m2 in women (n = 21) and #7.5 kg/m2 in men (n = 12). Components of energy balance (resting metabolic rate, physical activity thermogenesis, energy intake) and 24-h glycemic responses were measured under free-living conditions with random allocation to daily breakfast ($700 kcal before 1100) or extended fasting (0 kcal until 1200) for 6 wk, with baseline and follow-up measures of health markers (eg, hematology/biopsies). Results: Contrary to popular belief, there was no metabolic adaptation to breakfast (eg, resting metabolic rate stable within 11 kcal/d), with limited subsequent suppression of appetite (energy intake remained 539 kcal/d greater than after fasting; 95% CI: 157, 920 kcal/d). Rather, physical activity thermogenesis was markedly higher with breakfast than with fasting (442 kcal/d; 95% CI: 34, 851 kcal/d). Body mass and adiposity did not differ between treatments at baseline or follow-up and neither did adipose tissue glucose uptake or systemic indexes of cardiovascular health. Continuously measured glycemia was more variable during the afternoon and evening with fasting than with breakfast by the final week of the intervention (CV: 3.9%; 95% CI: 0.1%, 7.8%). Conclusions: Daily breakfast is causally linked to higher physical activity thermogenesis in lean adults, with greater overall dietary energy intake but no change in resting metabolism. Cardiovascular health indexes were unaffected by either of the treatments, but breakfast maintained more stable afternoon and evening glycemia than did fasting

An innovative physical activity intervention in overweight and obese adults using continuous glucose monitor

Introduction: Regular physical activity (PA) lowers the risk of endometrial, breast, and colorectal cancer. However, nearly half of American adults are not sufficiently active. The physical inactivity rate is even higher among the overweight and obese population, which, in combination with the unfavorable effect of excess body weight, puts this population at a greater risk for cancer. Advancements in wearable sensor technology provide opportunities for personalized approaches to increase motivation to be active. The current pilot study used continuous glucose monitors (CGM) to demonstrate the immediate, physiological benefits of PA. Methods: Insufficiently active (\u3c150 mins of moderate intensity PA per week) overweight and obese (body mass index 25 kg/m2) adults (18-65 years old) without diabetes are being recruited to participate in this pilot intervention. Upon enrollment, participants go through a one-on-one PA education session that includes a discussion about the health benefits of recommended PA levels, demonstration of the acute effect of PA on daily glucose patterns using a web-based glucose simulator, calculation of personal heart rate zones for moderate intensity PA, and development of an exercise plan. After the education session, participants are given a Fitbit Alta HR wristband and are instructed to wear it over the next 10 days. Participants are also given a Freestyle Libre CGM, which consists of a sensor and a reader. The sensor is inserted into the back of the upper arm to collect interstitial glucose data every 15 minutes for 10 days after activation. The reader displays current glucose readings and a graph of the 8 previous hours of glucose data upon scanning the sensor. Participants are instructed to scan the sensor at least 4 times a day and are encouraged to achieve at least 150 minutes of moderate intensity PA each week. At the end of the self-monitoring period, participants return their Fitbit and have their CGM sensor removed. Results: Thus far, 10 of 20 participants have enrolled and completed the study. These participants have been 100% female, 70% obese, and 20% Hispanic with a mean age of 41.5 (SD = 8.6) years old. On average, participants scanned their sensor 6 times each day and wore the Fitbit for all 10 days. On average, participants highly rated each component of the education session (on a 5-point scale) for improving their PA knowledge (mean = 4.4), increasing their PA motivation (mean = 4.4), and providing personally-relevant information (mean = 4.6). Participants also reported a very positive experiences wearing the CGM, with mean ratings (on a 5-point scale) of 4.8 for usability, 4.6 for convenience, 4.9 for value, 4.9 for relevance, and 4.7 for motivating. Conclusion: These preliminary data suggest that using a CGM to motivate PA among nondiabetic adults is feasible and acceptable. Future research will be conducted to examine the effect a CGM-based PA intervention has on changing PA behavior

A Low-Glucose Eating Pattern Improves Biomarkers of Postmenopausal Breast Cancer Risk: An Exploratory Secondary Analysis of a Randomized Feasibility Trial

Postmenopausal breast cancer is the most common obesity-related cancer death among women in the U.S. Insulin resistance, which worsens in the setting of obesity, is associated with higher breast cancer incidence and mortality. Maladaptive eating patterns driving insulin resistance represent a key modifiable risk factor for breast cancer. Emerging evidence suggests that time-restricted feeding paradigms (TRF) improve cancer-related metabolic risk factors; however, more flexible approaches could be more feasible and effective. In this exploratory, secondary analysis, we identified participants following a low-glucose eating pattern (LGEP), defined as consuming energy when glucose levels are at or below average fasting levels, as an alternative to TRF. Results show that following an LGEP regimen for at least 40% of reported eating events improves insulin resistance (HOMA-IR) and other cancer-related serum biomarkers. The magnitude of serum biomarkers changes observed here has previously been shown to favorably modulate benign breast tissue in women with overweight and obesity who are at risk for postmenopausal breast cancer. By comparison, the observed effects of LGEP were similar to results from previously published TRF studies in similar populations. These preliminary findings support further testing of LGEP as an alternative to TRF and a postmenopausal breast cancer prevention strategy. However, results should be interpreted with caution, given the exploratory nature of analyses.</jats:p