Metabolic dysfunction and excess accumulation of adipose tissue are detrimental side effects from breast cancer treatment. Diet and physical activity are important treatments for metabolic abnormalities, yet patient compliance can be challenging during chemotherapy treatment. Time-restricted eating (TRE) is a feasible dietary pattern where eating is restricted to 8 h/d with water-only fasting for the remaining 16 h. The purpose of this study is to evaluate the effect of a multimodal intervention consisting of TRE, healthy eating, and reduced sedentary time during chemotherapy treatment for early-stage (I–III) breast cancer on accumulation of visceral fat (primary outcome), other fat deposition locations, metabolic syndrome and cardiovascular disease risk (secondary outcomes) compared with usual care. The study will be a two-site, two-arm, parallel-group superiority randomised control trial enrolling 130 women scheduled for chemotherapy for early-stage breast cancer. The intervention will be delivered by telephone, including 30–60-minute calls with a registered dietitian who will provide instructions on TRE, education and counselling on healthy eating, and goal setting for reducing sedentary time. The comparison group will receive usual cancer and supportive care including a single group-based nutrition class and healthy eating and physical activity guidelines. MRI, blood draws and assessment of blood pressure will be performed at baseline, after chemotherapy (primary end point), and 2-year follow-up. If our intervention is successful in attenuating the effect of chemotherapy on visceral fat accumulation and cardiometabolic dysfunction, it has the potential to reduce risk of cardiometabolic disease and related mortality among breast cancer survivors.

This secondary analysis examined the influence of changes in physical activity (PA), sedentary time and energy expenditure (EE) during dietary energy restriction on the rate of weight loss (WL) and 1-year follow-up weight change in women with overweight/obesity. Measurements of body weight and composition (air displacement plethysmography), RMR (indirect calorimetry), total daily EE (TDEE) and activity EE (AEE), minutes of PA and sedentary time (PA monitor) were taken at baseline, after 2 weeks, after ≥5 % WL or 12 weeks of continuous (25 % daily energy deficit) or intermittent (75 % daily energy deficit alternated with ad libitum day) energy restriction, and at 1-year post-WL. The rate of WL was calculated as total %WL/number of dieting weeks. Data from both groups were combined for analyses. Thirty-seven participants (aged 35 (sd 10) years; BMI = 29·1 (sd 2·3) kg/m2) completed the intervention (WL = –5·9 (sd 1·6) %) and 18 returned at 1-year post-WL (weight change=+4·5 (sd 5·2) %). Changes in sedentary time at 2 weeks were associated with the rate of WL during energy restriction (r = –0·38; P = 0·03). Changes in total (r = 0·54; P < 0·01), light (r = 0·43; P = 0·01) and moderate-to-vigorous PA (r = 0·55; P < 0·01), sedentary time (r = –0·52; P < 0·01), steps per d (r = 0·39; P = 0·02), TDEE (r = 0·46; P < 0·01) and AEE (r = 0·51; P < 0·01) during energy restriction were associated with the rate of WL. Changes in total (r = –0·50; P = 0·04) and moderate-to-vigorous PA (r = –0·61; P = 0·01) between post-WL and follow-up were associated with 1-year weight change (r = –0·51; P = 0·04). These findings highlight that PA and sedentary time could act as modifiable behavioural targets to promote better weight outcomes during dietary energy restriction and/or weight maintenance.

Little is known about the relationship between socioeconomic position (SEP) and duration and patterning of objectively measured sedentary time (ST) among adults, especially adults at high risk of diabetes. The aim of this study was to examine cross-sectional associations of SEP with ST (total, prolonged ST, breaks in ST) and self-reported TV time among pregnant women at risk of gestational diabetes in the UK. At 20 weeks’ gestation, pregnant women (n=174) wore an activPAL accelerometer and reported their usual TV time. Generalized linear mixed models were used to test associations of education, household income and area-level deprivation (separately and with mutual adjustment) with total ST, prolonged ST and breaks in ST. Logistic regression models were used to test associations between SEP indicators and high (≥2h/day) TV time. Those with the lowest education, lowest household income and highest area-level deprivation had the lowest ST and lowest prolonged ST. After mutual adjustment, area-level deprivation remained associated with total ST (β=0.10 [0.01, 0.20]). There was an inverse association between area-level deprivation and breaks in sedentary time (exp(b)=1.11 [1.01, 1.22]). Education was the only SEP correlate of high TV time, with more of those with least education reporting high TV time; this association persisted after adjustment for household income and area-level deprivation. The association between SEP and total and prolonged ST (positive) was the opposite of the association between education and high TV time (negative) in this sample of high-risk pregnant women. These findings should inform interventions to reduce sedentary time.

The interdependence among eating behaviour (EB), physical activity (PA) and sedentary time (ST) suggests simultaneously identifying homogeneous profiles and describing their changes. This study aimed to (1) identify cross-sectional lifestyle behaviour profiles and their 2-year changes among French school-age adolescents and (2) identify factors associated with these profiles and changes. Longitudinal data from adolescents who participated in the PRomotion de l’ALIMentation et de l’Activité Physique trial were used. PA and ST were assessed with the International Physical Activity Questionnaire and EB with a FFQ. Profiles at baseline and their changes were identified by latent transition analysis. Multinomial logistic regression models were used to identify factors associated with profiles and their changes. Among 2390 adolescents included (14–18 years), five baseline profiles that differed mainly in EB were identified: ‘healthy diet and high PA (7·9 %)’, ‘big eater and moderate to high PA (23·8 %)’, ‘healthy diet and low PA (31·2 %)’, ‘restrictive diet and moderate PA (20·6 %)’ and ‘sugar products, nibbling and moderate PA (16·5 %)’. Young adolescents, those who were overweight or obese and socially advantaged, were more in the ‘healthy diet and low PA’ than others. Boys, older and socially less advantaged adolescents exhibited more ‘unfavourable’ than ‘mixed’ changes, while adolescents with overweight or obesity had less ‘unfavourable’ than ‘mixed’ changes. In conclusion, adolescents were twice the number in the least than the most favourable profile. Findings highlighted the importance of EB among adolescents and suggest taking adolescents’ sociodemographic and weight characteristics into account in interventions aimed at acting on adolescents’ behaviours.