Obesity-related hepatic steatosis is a major risk factor for metabolic and cardiovascular disease. Fat reduced hypocaloric diets are able to relieve the liver from ectopically stored lipids. We hypothesized that the widely used low carbohydrate hypocaloric diets are similarly effective in this regard. A total of 170 overweight and obese, otherwise healthy subjects were randomized to either reduced carbohydrate (n 5 84) or reduced fat (n 5 86), total energy restricted diet (230% of energy intake before diet) for 6 months. Body composition was estimated by bioimpedance analyses and abdominal fat distribution by magnetic resonance tomography. Subjects were also submitted to fat spectroscopy of liver and oral glucose tolerance testing. In all, 102 subjects completed the diet intervention with measurements of intrahepatic lipid content. Both hypocaloric diets decreased body weight, total body fat, visceral fat, and intrahepatic lipid content. Subjects with high baseline intrahepatic lipids (>5.56%) lost %7-fold more intrahepatic lipids compared with those with low baseline values (<5.56%) irrespective of diet composition. In contrast, changes in visceral fat mass and insulin sensitivity were similar between subgroups, with low and high baseline intrahepatic lipids. Conclusion: A prolonged hypocaloric diet low in carbohydrates and high in fat has the same beneficial effects on intrahepatic lipid accumulation as the traditional low-fat hypocaloric diet. The decrease in intrahepatic lipids appears to be independent of visceral fat loss and is not tightly coupled with changes in whole body insulin sensitivity during 6 months of an energy restricted diet. (HEPATOLOGY 2011;53:1504-1514
Previous studies suggested that hypoxia and exercise may have a synergistic effect on cardiovascular and metabolic risk factors. We conducted a single blind study in overweight to obese subjects to test the hypothesis that training under hypoxia (HG, n = 24, FiO(2) = 15%) results in similar or even greater improvement in body weight and metabolic risk markers compared with exercise under normoxia (NG, n = 21, FiO(2) = 21%). After an initial metabolic evaluation including incremental exercise testing, subjects trained in normoxic or hypoxic conditions thrice weekly over a 4-week period at a heart rate corresponding to 65% of maximum oxygen uptake (VO(2max)). The experimental groups were similar at the start of the investigation and weight stable during the training period. Subjects in the hypoxia group trained at a significantly lower workload (P < 0.05). Yet, both groups showed similar improvements in VO(2max) and time to exhaustion. Respiratory quotient and lactate at the anaerobic threshold as well as body composition improved more in the hypoxia group. We conclude that in obese subjects, training in hypoxia elicits a similar or even better response in terms of physical fitness, metabolic risk markers, and body composition at a lower workload. The fact that workload and, therefore, mechanic strain can be reduced in hypoxia could be particularly beneficial in obese patients with orthopedic comorbidities.
Endurance training in hypoxia over a 4-wk period elicits a similar or even better response in terms of cardiovascular and metabolic risk factors than endurance exercise in normoxia. The fact that workload and, therefore, mechanic strain can be reduced in hypoxia could be particularly beneficial in obese patients and in patients with orthopedic conditions.
OBJECTIVEWeight loss reduces abdominal and intrahepatic fat, thereby improving metabolic and cardiovascular risk. Yet, many patients regain weight after successful diet-induced weight loss. Long-term changes in abdominal and liver fat, along with liver test results and insulin resistance, are not known.RESEARCH DESIGN AND METHODSWe analyzed 50 overweight to obese subjects (46 ± 9 years of age; BMI, 32.5 ± 3.3 kg/m2; women, 77%) who had participated in a 6-month hypocaloric diet and were randomized to either reduced carbohydrates or reduced fat content. Before, directly after diet, and at an average of 24 (range, 17–36) months follow-up, we assessed body fat distribution by magnetic resonance imaging and markers of liver function and insulin resistance.RESULTSBody weight decreased with diet but had increased again at follow-up. Subjects also partially regained abdominal subcutaneous and visceral adipose tissue. In contrast, intrahepatic fat decreased with diet and remained reduced at follow-up (7.8 ± 9.8% [baseline], 4.5 ± 5.9% [6 months], and 4.7 ± 5.9% [follow-up]). Similar patterns were observed for markers of liver function, whole-body insulin sensitivity, and hepatic insulin resistance. Changes in intrahepatic fat und intrahepatic function were independent of macronutrient composition during intervention and were most effective in subjects with nonalcoholic fatty liver disease at baseline.CONCLUSIONSA 6-month hypocaloric diet induced improvements in hepatic fat, liver test results, and insulin resistance despite regaining of weight up to 2 years after the active intervention. Body weight and adiposity measurements may underestimate beneficial long-term effects of dietary interventions.
Background: The number of people preferring plant-based nutrition is growing continuously in the western world. Vegetarianism and veganism are also becoming increasingly popular among individuals participating in sport. However, whether recreationally active vegetarian and vegan populations can meet their nutritional needs is not clear. Methods: The purpose of this cross-sectional study was to compare the nutrient intake of omnivorous (OMN, n = 27), lacto-ovo vegetarian (LOV, n = 25) and vegan (VEG, n = 27) recreational runners (two to five training sessions per week) with intake recommendations of the German, Austrian and Swiss Nutrition Societies (Deutsche, Österreichische und Schweizerische Gesellschaften für Ernährung, D-A-CH) for the general population. Lifestyle factors and supplement intake were examined via questionnaires; dietary habits and nutrient intake were determined based on 3-day dietary records. Results: More than half of each group did not reach the recommended energy intake (.3 MJ). Carbohydrate intake was slightly below the recommendations of > 50 EN% in OMN (46.7,, while LOV (49.4, 45.5-53.3 EN%) and VEG (55.2, 51.4-59.0 EN%) consumed adequate amounts (p = 0.003). The recommended protein intake of 0.8 g/kg body weight (D-A-CH) was exceeded in all three groups (OMN: 1.50, 1.27-1.66; LOV: 1.34, 1.09-1.56; VEG: 1.25; 1.07-1.42 g/kg BW; p = 0.047). Only VEG (26.3, 22.7-29.8 EN%) did not achieve the recommended fat intake of 30 EN%. The supply of micronutrients, such as vitamin D and cobalamin, was dependent on supplement intake. Additionally, female OMN and LOV achieved the recommended daily intake of 15 mg iron only after supplementation, while VEG consumed adequate amounts solely via food.Conclusion: All three groups were sufficiently supplied with most nutrients despite the exceptions mentioned above. The VEG group even showed advantages in nutrient intake (e.g. carbohydrates, fiber and iron) in comparison to the other groups. However, the demand for energy and several macro-and micronutrients might be higher for athletes. Thus, it is also necessary to analyze the endogenous status of nutrients to evaluate the influence of a vegetarian and vegan diet on the nutrient supply of athletes.
Background Metabolic syndrome is a predisposing factor for cardiovascular and metabolic disease, but also has socioeconomic relevance by affecting the health and productivity of workers. We tested the effect of regular telemonitoring-supported physical activity on metabolic syndrome severity and work ability in company employees.Methods This was a prospective, randomised, parallel-group, and assessor-blind study done in workers in the main Volkswagen factory (Wolfsburg, Germany). Volunteers with diagnosed metabolic syndrome according to American Heart Association/National Heart, Lung, and Blood Institute criteria were randomly assigned (1:1) to a 6-month lifestyle intervention focusing on regular exercise (exercise group), or to a waiting-list control group, using a computer-based assignment list with variable block length. Participants in the exercise group received individual recommendations for exercise at face-to-face meetings and via a smartphone application, with the aim of doing 150 min physical activity per week. Activities were supervised and adapted using activity-monitor data, which were transferred to a central database. Participants in the control group continued their current lifestyle and were informed about the possibility to receive the supervised intervention after study completion. The primary outcome was the change in metabolic syndrome severity (metabolic syndrome Z score) after 6 months in the intention-to treat population. This trial is registered with ClinicalTrials.gov, number NCT03293264, and is closed to new participants. Findings 543 individuals were screened between Oct 10, 2017, and Feb 27, 2018, of whom 314 (mean age 48 years [SD 8]) were randomly assigned to receive the intervention (n=160; exercise group) or to a waiting list (n=154; control group). The mean metabolic syndrome Z score for the exercise group was significantly reduced after the 6-month intervention period (0•93 [SD 0•63] before and 0•63 [0•64] after the intervention) compared with the control group (0•95 [0•55] and 0•90 [0•61]; difference between groups -0•26 [95% CI -0•35 to -0•16], p<0•0001). We documented 11 adverse events in the exercise group, with only one event (a twisted ankle) regarded as directly caused by the intervention.Interpretation A 6-month exercise-focused intervention using telemonitoring systems reduced metabolic syndrome severity. This form of intervention shows significant potential to reduce disease risk, while also improving mental health, work ability, and productivity-related outcomes for employees at high risk for cardiovascular and metabolic disease.Funding Audi BKK health insurance and the German Research Foundation through the Cluster of Excellence REBIRTH.
Background In search of the right nutrition for the athlete, numerous nutritional strategies and diets were discussed over time. However, the influence of plant-based diets, especially veganism, on exercise capacity has not been clarified. Methods We conducted a cross-sectional study to compare the exercise capacity of vegan (VEG, n = 24), lacto-ovo-vegetarian (LOV, n = 26) and omnivorous (OMN, n = 26) recreational runners. To determine maximal exercise capacity, participants performed an incremental exercise test on a bicycle ergometer until voluntary exhaustion. During the test capillary blood samples were taken at several time points for the measurement of arterial lactate [lac] and glucose [glc] concentrations. To determine nutrient intake, a 24 h dietary recall was conducted. Results The groups showed comparable training habits in terms of training frequency (mean 3.08 ± 0.90 time/wk., p = 0.735), time (mean 2.93 ± 1.34 h/wk., p = 0.079) and running distance (mean 29.5 ± 14.3 km/wk., p = 0.054). Moreover, similar maximum power output (P maxBW ) was observed in all three groups (OMN: 4.15 ± 0.48 W/kg, LOV: 4.20 ± 0.47 W/kg, VEG: 4.16 ± 0.55 W/kg; p = 0.917) and no differences regarding [lac] throughout the exercise test and maximum lactate could be observed between the groups (OMN: 11.3 ± 2.19 mmol/l, LOV: 11.0 ± 2.59 mmol/l, VEG: 11.9 ± 1.98 mmol/l; p = 0.648). Conclusion The data indicate that each examined diet has neither advantages nor disadvantages with regard to exercise capacity. These results suggest that a vegan diet can be a suitable alternative for ambitious recreational runners. Trial registration German Clinical Trials Register ( DRKS00012377 ). Registered on 28 April 2017
ClinicalTrials.gov NCT00956566.
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