Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet

Purpose: Although high-intensity interval training (HIIT) and moderate-intensity continuous exercise have comparable health outcomes in the laboratory setting, effectiveness studies in real-world environments are lacking. The aim of this study was to determine the effectiveness of an unsupervised HIIT program in overweight/obese adults over 12 months. Methods: Two hundred and fifty overweight/obese adults could choose HIIT or current exercise guidelines of 30 min·d⁻¹ moderate-intensity exercise. HIIT participants received a single training session and were advised to independently perform HIIT three times per week using a variety of protocols. Mixed models, with a random effect for participant, compared differences in weight, body composition, blood pressure, aerobic fitness, physical activity, and blood indices at 12 months, adjusting for relevant baseline variables. Results: Forty-two percent (n = 104) of eligible participants chose HIIT in preference to current guidelines. At 12 months, there were no differences between exercise groups in weight (adjusted difference HIIT vs conventional = −0.44 kg; 95% confidence interval [CI] = −2.5 to 1.6) or visceral fat (−103 cm³; −256 to 49), although HIIT participants reported greater enjoyment of physical activity (P = 0.01). Evidence of adherence to ≥2 sessions per week of unsupervised HIIT (from HR monitoring) declined from 60.8% at baseline to 19.6% by 12 months. Participants remaining adherent to HIIT over 12 months (23%) were more likely to be male (67% vs 36%, P = 0.03), with greater reductions in weight (−2.7 kg; −5.2 to 0.2) and visceral fat (−292 cm³; −483 to −101) than nonadherent participants. Conclusions: HIIT was well accepted by overweight adults, and opting for HIIT as an alternative to standard exercise recommendations led to no difference in health outcomes after 12 months. Although regular participation in unsupervised HIIT declined rapidly, those apparently adherent to regular HIIT demonstrated beneficial weight loss and visceral fat reduction. Trial Registration: Australian New Zealand Clinical Trials Registry (ACTRN12615000010594), retrospectively registered.

Intermittent fasting (IF) and Paleolithic (Paleo) diets produce weight loss in controlled trials, but minimal evidence exists regarding long-term efficacy under free-living conditions without intense dietetic support. This exploratory, observational analysis examined adherence, dietary intake, weight loss, and metabolic outcomes in overweight adults who could choose to follow Mediterranean, IF, or Paleo diets, and standard exercise or high-intensity interval training (HIIT) programs, as part of a 12-mo randomized controlled trial investigating how different monitoring strategies influenced weight loss (control, daily self-weighing, hunger training, diet/exercise app, brief support). A total of 250 overweight [BMI (in kg/m2) ≥27] healthy adults attended an individualized dietary education session (30 min) relevant to their self-selected diet. Dietary intake (3-d weighed diet records), weight, body composition, blood pressure, physical activity (0, 6, and 12 mo), and blood indexes (0 and 12 mo) were assessed. Mean (95% CI) changes from baseline were estimated using regression models. No correction was made for multiple tests. Although 54.4% chose IF, 27.2% Mediterranean, and 18.4% Paleo diets originally, only 54% (IF), 57% (Mediterranean), and 35% (Paleo) participants were still following their chosen diet at 12 mo (self-reported). At 12 mo, weight loss was -4.0 kg (95% CI: -5.1, -2.8 kg) in IF, -2.8 kg (-4.4, -1.2 kg) in Mediterranean, and -1.8 kg (-4.0, 0.5 kg) in Paleo participants. Sensitivity analyses showed that, due to substantial dropout, these may be overestimated by ≤1.2 kg, whereas diet adherence increased mean weight loss by 1.1, 1.8, and 0.3 kg, respectively. Reduced systolic blood pressure was observed with IF (-4.9 mm Hg; -7.2, -2.6 mm Hg) and Mediterranean (-5.9 mm Hg; -9.0, -2.7 mm Hg) diets, and reduced glycated hemoglobin with the Mediterranean diet (-0.8 mmol/mol; -1.2, -0.4 mmol/mol). However, the between-group differences in most outcomes were not significant and these comparisons may be confounded due to the nonrandomized design. Small differences in metabolic outcomes were apparent in participants following self-selected diets without intensive ongoing dietary support, even though dietary adherence declined rapidly. However, results should be interpreted with caution given the exploratory nature of analyses. This trial was registered with the Australian New Zealand Clinical Trials Registry as ACTRN12615000010594 at https://www.anzctr.org.au.

Objective: To determine the effectiveness of various monitoring strategies on weight loss, body composition, blood markers, exercise, and psychosocial indices in adults with overweight and obesity following a 12‐month weight loss program.Methods: Two hundred fifty adults with BMI ≥ 27 were randomized to brief, monthly, individual consults, daily self‐monitoring of weight, self‐monitoring of diet using MyFitnessPal, self‐monitoring of hunger, or control over 12 months. All groups received diet and exercise advice, and 171 participants (68.4%) remained at 12 months.Results: No significant differences in weight, body composition, blood markers, exercise, or eating behavior were apparent between those in the four monitoring groups and the control condition at 12 months (all P ≥ 0.053). Weight differences between groups ranged from −1.1 kg (−3.8 to 1.6) to 2.2 kg (−1.0 to 5.3). However, brief support and hunger training groups reported significantly lower scores for depression (difference [95% CI]: −3.16 [−5.70 to −0.62] and −3.05 [−5.61 to −0.50], respectively) and anxiety (−1.84, [−3.67 to −0.02]) scores than control participants.Conclusions: Although adding a monitoring strategy to diet and exercise advice did not further increase weight loss, no adverse effects on eating behavior were observed, and some monitoring strategies may even benefit mental health.

Monitoring blood glucose prior to eating can teach individuals to eat only when truly hungry, but how adherence to ‘hunger training’ influences weight loss and eating behaviour is uncertain. This exploratory, secondary analysis from a larger randomized controlled trial examined five indices of adherence to ‘hunger training’, chosen a priori, to examine which adherence measure best predicted weight loss over 6 months. We subsequently explored how the best measure of adherence influenced eating behavior in terms of intuitive and emotional eating. Retention was 72% (n = 36/50) at 6 months. Frequency of hunger training booklet entry most strongly predicted weight loss, followed by frequency of blood glucose measurements. Participants who completed at least 60 days of booklet entry (of recommended 63 days) lost 6.8 kg (95% CI: 2.6, 11.0; p < 0.001) more weight than those who completed fewer days. They also had significantly higher intuitive eating scores than those who completed 30 days or less of booklet entry; a difference (95% CI) of 0.73 (0.12, 1.35) in body-food choice congruence and 0.79 (0.06, 1.51) for eating for physical rather than emotional reasons. Adherent participants also reported significantly lower scores for emotional eating of −0.70 (−1.13, −0.27). Following hunger training and focusing on simply recording ratings of hunger on a regular basis can produce clinically significant weight loss and clinically relevant improvements in eating behaviour.