The Effects of Ketogenic Diet on Insulin Sensitivity and Weight Loss, Which Came First: The Chicken or the Egg?

The ketogenic diet (KD) is, nowadays, considered an interesting nutritional approach for weight loss and improvement in insulin resistance. Nevertheless, most of the studies available in the literature do not allow a clear distinction between its effects on insulin sensitivity per se, and the effects of weight loss induced by KDs on insulin sensitivity. In this review, we discuss the scientific evidence on the direct and weight loss mediated effects of KDs on glycemic status in humans, describing the KD's biochemical background and the underlying mechanisms.

Physical Performance of Brazilian Military Policemen: A Longitudinal Analysis by Occupational Specialties.

Maintenance of good levels of physical fitness is essential during occupational tasks for the general health of the military police. However, no studies have evaluated longitudinal changes in the physical fitness of Brazilian military police officers according to their specialties. Thus, the objective of the current study was to analyze the changes in the physical fitness of military police officers according to their specialty, over a period of five years. Retrospective data (2015-2019) from 290 police officers were analyzed, including age and physical fitness tests (12-min run test, sit-ups, push-ups, and pull-ups on the bar). The sample was divided into four groups (Specialized; Border; Urban; and Environmental). ANCOVA was used to describe differences in physical fitness components between groups of police officers after adjusting for age. Initial fitness was higher among police officers in the Specialized group (i.e., those with greater physical demands). During the five-year follow-up period, there was an age-related decrease in physical capacity for all groups, regardless of specialty. However, Urban police showed improvement in running and sit-up tests (p < 0.05) over time. Changes in physical capacity during follow-up differed depending on the physical component analyzed and the occupational specialty.

Changes in Compliance With Physical Activity Guidelines and Cardiovascular Disease Mortality.

BACKGROUND: The effects of compliance with the US Physical Activity (PA) Guidelines and changes in compliance over time on cardiovascular disease (CVD) mortality are unknown. METHODS: Male participants in the Aerobics Center Longitudinal Study (n = 15,411; 18-100 y) reported leisure-time PA between 1970 and 2002. The frequency of and time spent in PA were converted into metabolic equivalent minutes per week. The participants were classified into remained inactive, became active, became inactive, or remained active groups according to their achievement of the PA guidelines along the follow-up, equivalent here to at least 500 metabolic equivalent minutes of PA per week. Cox regression adjusted for different models was used for the analyses, using age, body mass index, smoking and drinking status, hypertension, diabetes, hypercholesterolemia, and parental history of CVD. RESULTS: Over a mean follow-up of 6.2 years, 439 CVD deaths occurred. Consistently meeting the PA guidelines, compared with not meeting, was associated with a 54% (95% confidence interval, 0.32-0.67) decreased risk of CVD mortality. After controlling for all potential confounders, the risk reduction was 47% (95% confidence interval, 0.36-0.77). CONCLUSIONS: Maintaining adherence to the PA guidelines produces substantial reductions in the risk of CVD deaths in men. Furthermore, discontinuing compliance with the guidelines may offset the beneficial effects on longevity.

Application of the Rosetta Stone to understand how much MVPA preschoolers accumulate: A systematic review.

OBJECTIVES: This study illustrates the utility of the Rosetta Stone equations for comparing estimates of preschool-age children's moderate-to-vigorous physical activity (MVPA) across studies utilizing different cutpoints. DESIGN: Systematic review. METHODS: A search of online databases was conducted to identify studies that reported daily minutes of MVPA in preschoolers using the cutpoints from which Rosetta Stone equations have been developed. Mean MVPA minday-1 from each study and the transformed estimate using the Rosetta Stone equations were compared across 7 sets of cutpoints. The weighted mean was used to calculate absolute differences between the MVPA estimates of studies using the same cutpoints (e.g all studies that have used Pate cutpoint), and from all of the remaining studies using different cutpoints (e.g., all remaining studies that have not used Pate cutpoint), before and after the Rosetta Stone transformation. RESULTS: A total of 33 manuscripts met the eligibility criteria and reported MVPA for 12,178 preschoolers (50% girls). The mean MVPA for the total sample ranged from 21.1 (Puyau cutpoint) to 288.6 (Freedson cutpoints) minday-1. The difference between studies using the same cutpoint and estimates from remaining studies using different cutpoints was 82.4 and 80.0minday-1 for boys and girls, respectively. These differences were reduced to approximately 14minday-1 for boys and girls, after Rosetta Stone transformations. CONCLUSIONS: The Rosetta Stone equations substantially reduced the differences across studies that utilize different cutpoints and improved the ability to interpret findings across studies. Future equations should be developed for sedentary and total physical activity, as well as, comparisons across different devices and placements.