Background The high-fat ketogenic diet (KD) has become an increasingly popular diet not only in overweight/obese populations, or those with clinical conditions, but also in healthy non-overweight populations. Objective Because there are concerns about the association between high-fat diets and cognitive decline, this study aimed to determine the effects of a KD compared with an isocaloric high-carbohydrate, low-fat (HCLF) diet on cognitive function, sleep, and mood in healthy, normal-weight individuals. Methods Eleven healthy, normal-weight participants (mean age: 30 ± 9 y) completed this randomized, controlled, crossover study. Participants followed 2 isocaloric diets—an HCLF diet (55% carbohydrate, 20% fat, and 25% protein) and a KD (15% carbohydrate, 60% fat, and 25% protein)—in a randomized order for a minimum of 3 wk, with a 1-wk washout period between diets. Measures of β-hydroxybutyrate confirmed that all participants were in a state of nutritional ketosis during post-KD assessments (baseline: 0.2 ± 0.2 mmol/L; KD: 1.0 ± 0.5 mmol/L; washout: 0.2 ± 0.1 mmol/L; and HCLF: 0.3 ± 0.2 mmol/L). Cognitive function was assessed using a validated, psychological computer-based test battery before and after each diet. Subjective measures of mood and sleep were also monitored throughout the study using validated scales. Results Three weeks of sustained nutritional ketosis, compared with the HCLF diet, had no effect on speed and accuracy responses in tasks designed to measure vigilance (speed: P = 0.39, Cohen's d = 0.26; accuracy: P = 0.99, Cohen's d = 0.04), visual learning and memory (speed: P = 0.99, Cohen's d = 0.04; accuracy: P = 0.99, Cohen's d = 0.03), working memory (speed: P = 0.62, Cohen's d = 0.26; accuracy: P = 0.98, Cohen's d = 0.07), and executive function (speed: P = 0.60, Cohen's d = 0.31; accuracy: P = 0.90, Cohen's d = 0.19). Likewise, mood, sleep quality, and morning vigilance did not differ (P > 0.05) between the dietary interventions. Conclusion The results of our randomized, crossover, controlled study suggest that 3 wk of sustained nutritional ketosis had no effect on cognitive performance, mood, or subjective sleep quality in a sample of healthy individuals. This trial was registered in the Pan African Clinical Trial Registry as PACTR201707002406306.

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BackgroundMany physiological health benefits observed after following a ketogenic diet (KD) can be attributed to the associated weight loss. The KD has become more prominent as a popular health choice, not only in obese/overweight individuals, but also in healthy adults. The study aims to determine the effects of a KD, independent of weight loss, on various aspects of physiological health including: sleep, thyroid function, cognition, and cardio-metabolic health. The study will also aim to determine whether a change in basal metabolic rate may be associated with any changes observed.MethodsTwenty healthy men and women between 18 and 50 years of age will take part in this study. In a randomized controlled, cross-over design, participants will follow two isocaloric diets: a high-carbohydrate, low-fat diet (55% CHO, 20% fat, 25% protein) and a KD (15% CHO, 60% fat, 25% protein). Each dietary intervention will last for a minimum of 3 weeks, with a 1-week washout period in between. Before and after each diet, participants will be assessed for sleep quality, cognitive function, thyroid function, and basal metabolic rate. A blood sample will also be taken for the measurement of cardio-metabolic and immune markers.DiscussionThe present study will help in understanding the potential effects of a KD on aspects of physiological health in healthy adults, without the confounding factor of weight loss. The study aims to fill a significant void in the academic literature with regards to the benefits and/or risks of a KD in a healthy population, but will also explore whether diet-related metabolic changes may be responsible for the changes observed in physiological health.Trial registrationPan African Clinical Trial Registry (www.pactr.org), trial number: PACTR201707002406306. Registered on 20 July 2017.Electronic supplementary materialThe online version of this article (10.1186/s13063-018-2462-5) contains supplementary material, which is available to authorized users.

This study describes self-reported physical activity (PA), motivation to exercise, physical and mental health and feelings towards PA during the March-May 2020 COVID-19 lockdown in New Zealand. Adults over the age of 18 years (n = 238; 80.2% female) completed the International Physical Activity Questionnaire (IPAQ), the Behavioural Regulation in Exercise Questionnaire 3, the Short Form-36 and open-ended questions about PA through an anonymous online survey. Regular exercise was undertaken by 85% of respondents prior to lockdown, but only 49.8% were able to maintain their usual level of PA. Although respondents were considered sufficiently physically active from the IPAQ, 51.5% reported not being able to maintain their usual level of PA primarily due to the closure of their gym facilities. Sixty percent of respondents reported that PA had a positive effect on their overall wellbeing. When asked to specify which aspects of wellbeing were affected, the effect on mental health was reported the most while the effect on body image or fitness was reported the least. Strategies to increase or maintain engagement in physical activity during lockdowns should be encouraged to promote positive mental health during the COVID-19 pandemic.

ORIGINAL RESEARCH Objectives. To compare the relationship between peak bone strain scores (PBSSs) calculated from physical activity (PA) questionnaires and accelerometry measures of PA with trabecular and cortical bone properties in prepubertal children. Methods. We compared PBSSs calculated from the bone-specific component of PA questionnaires with accelerometry and bone mass measures in 38 prepubertal children (mean 9.9 (standard deviation 1.3) years). Dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) were used to assess bone content and structure, and to estimate bone strength at the radial and tibial diaphysis and radial metaphysis. Results. The PBSS was reliable and reproducible with significant (p<0.001) intraclass correlation coefficients. There were significant correlations between PBSS and moderate (r=0.38; p=0.02), vigorous (r=0.36; p=0.03) and combined moderate-to vigorous-intensity activity counts (r=0.38; p=0.02). PBSS was significantly correlated to body size-adjusted bone mineral content at all sites scanned by DXA (r=0.33-0.48; p<0.05). Positive correlations were observed between PBSS and area, density and strength at the radius and tibia (r=0.40-0.64; p<0.05). Only vigorous activity was correlated to cortical area at the radial diaphysis (r=0.37; p=0.03) and bone strength at the tibial diaphysis (r=0.32; p=0.05). Activity as assessed by the PBSS explained a greater amount of variance in bone variables as measured by DXA and pQCT than accelerometer-measured PA. Conclusion. Accelerometer-measured moderate and vigorous habitual PA is associated with indices of cortical bone size and geometry in children, whereas light PA has no detectable association. Furthermore, the bone-specific questionnaire appears to be more strongly associated with bone outcomes than accelerometer-derived measures of PA.

Rehabilitation for isolated forms of dystonia, such as cervical or focal hand dystonia, is usually targeted towards the affected body part and focuses on sensorimotor control and motor retraining of affected muscles. Recent evidence, has revealed people who live with dystonia experience a range of functional and non-motor deficits that reduce engagement in daily activities and health-related quality of life, which should be addressed with therapeutic interventions. These findings support the need for a holistic approach to the rehabilitation of dystonia, where assessment and treatments involve non-motor signs and symptoms, and not just the dystonic body part. Most studies have investigated Cervical Dystonia, and in this population, it is evident there is reduced postural control and walking speed, high fear of falling and actual falls, visual compensation for the impaired neck posture, and a myriad of non-motor symptoms including pain, fatigue, sleep disorders and anxiety and depression. In other populations of dystonia, there is also emerging evidence of falls and reduced vision-related quality of life, along with the inability to participate in physical activity due to worsening of dystonic symptoms during or after exercise. A holistic approach to dystonia would support the management of a wide range of symptoms and signs, that if properly addressed could meaningfully reduce disability and improve quality of life in people living with dystonia.

Sitting time was lower during the message-receiving period, but the difference between groups was no longer apparent after the intervention.

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