Separate and combined effects of exercise training and weight loss on exercise efficiency and substrate oxidation.
Amati F, Dube JJ, Shay C, Goodpaster BH. University of Pittsburgh.
Purpose: Perturbations in body weight have been shown to affect energy expenditure and efficiency during physical activity. The separate effects of weight loss and exercise training on exercise efficiency or the proportion of energy derived from fat oxidation during physical activity, however, are not known. The purpose of this study was to determine the separate and combined effects of exercise training and weight loss on metabolic efficiency, economy and fat oxidation during steady state moderate submaximal exercise.
Methods: 64 sedentary older (67+/-.5) overweight to obese (30.7+/-.4kg/m(2)) volunteers completed four months of either diet induced weight loss (WL,n=11), exercise training (EX,n=36) or the combination of both interventions (WLEX,n=17). Energy expenditure, gross efficiency (GE), economy (EC) and proportion of energy expended from fat (EF) were determined during a one-hour submaximal (50% of VO2peak) cycle ergometry exercise before the intervention and at the same absolute work rate after the intervention.
Results: EX increased GE by 4.7+/-2.2%. EC was similarly increased by 4.2+/-2.1% by EX. The addition of concomitant WL to EX (WLEX) resulted in greater increases in GE (9.0+/-3.3%) compared to WL alone but not compared to EX alone. These effects remained after adjusting for changes in LBM. The proportion of energy derived from fat during the bout of moderate exercise increased with EX and WLEX but not with WL.
Conclusion: Exercise training, either alone or in combination with weight loss, increases both exercise efficiency and the utilization of fat during moderate physical activity in previously sedentary, obese older adults. Weight loss alone, however, neither significantly improves efficiency nor utilization of fat during exercise.
My Notes: Very cool study---more evidence that you need to change your LIFESTYLE and get in some exercise for benefits, not just dropping some weight
Resistance training and timed essential amino acids protect against the loss of muscle mass and strength during 28 days of bed rest and energy deficit.
Brooks N, Cloutier GJ, Cadena SM, Layne JE, Nelsen CA, Freed AM, Roubenoff R, Castaneda-Sceppa C. Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA. Spaceflight and bed rest (BR) result in losses of muscle mass and strength.
Resistance training (RT) and amino acid (AA) supplementation are potential countermeasures to minimize these losses. However, it is unknown if timing of supplementation with exercise can optimize benefits, particularly with energy deficit. We examined the effect of these countermeasures on body composition, strength, and insulin levels in 31 men (ages 31-55 yr) during BR (28 days) followed by active recovery (14 days). Subjects were randomly assigned to essential AA supplementation (AA group, n = 7); RT with AA given 3 h after training (RT group, n = 12); or RT with AA given 5 min before training (AART group, n = 12). Energy intake was reduced by 8 +/- 6%. Midthigh muscle area declined with BR for the AA > RT > AART groups: -11%, -3%, -4% (P = 0.05). Similarly, greatest losses in lower body muscle strength were seen in the AA group (-22%). These were attenuated in the exercising groups [RT (-8%) and AART (-6%; P < p =" 0.05)." style="font-weight: bold;">
Conclusion: Combined resistance training with AA (amino accid) supplementation pre- or postexercise attenuated the losses in muscle mass and strength by approximately two-thirds compared with AA supplement alone during BR and energy deficit. These data support the efficacy of combined AA and RT as a countermeasure against muscle wasting due to low gravity.
My Notes: See my last post about a protein carb drink around your training time! Very beneficial
The danger of weight loss in the elderly.
Miller SL, Wolfe RR. R.R. Wolfe, 4301 W. Markham St., #806, Little Rock, AR 72205, Ph:501-526-5708,Fax: 501-526-5710, e-mail:email@example.com. Aging is generally accompanied by weight loss made up of both fat mass and fat-free mass. As more people, including elderly, are overweight or obese, weight loss is recommended to improve health. Health risks are decreased in overweight children and adults by dieting and exercise, but the health benefits of weight loss in elderly, particularly by calorie restriction, are uncertain. Rapid unintentional weight loss in elderly is usually indicative of underlying disease and accelerates the muscle loss which normally occurs with aging. Intentional weight loss, even when excess fat mass is targeted also includes accelerated muscle loss which has been shown in older persons to correlate negatively with functional capacity for independent living. Sarcopenic obesity, the coexistence of diminished lean mass and increased fat mass, characterizes a population particularly at risk for functional impairment since both sarcopenia (relative deficiency of skeletal muscle mass and strength) and obesity have been shown to predict disability. However, indices of overweight and obesity such as body mass index (BMI) do not correlate as strongly with adverse health outcomes such as cardiovascular disease in elderly as compared to younger individuals. Further, weight loss and low BMI in older persons are associated with mortality in some studies. On the other hand, studies have shown improvement in risk factors after weight loss in overweight/obese elderly. The recent focus on pro-inflammatory factors related to adiposity suggest that fat loss could ameliorate some catabolic conditions of aging since some cytokines may directly impact muscle protein synthesis and breakdown. Simply decreasing weight may also ease mechanical burden on weak joints and muscle, thus improving mobility.
Conclusion: Until a strategy is proven whereby further loss of muscle mass can be prevented, weight loss by caloric restriction in individuals with sarcopenic obesity should likely be avoided.
My Notes: Ideally, you want to drop FAT and KEEP MUSCLE! Weight training and proper nutrition can help you do it
Exercise attenuates the weight-loss-induced reduction in muscle mass in frail obese older adults.
Frimel TN, Sinacore DR, Villareal DT. Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO, USA.
PURPOSE: To evaluate the effect of adding exercise to a hypocaloric diet on changes in ppendicular lean mass and strength in frail obese older adults undergoing voluntary weight loss.
METHODS: Thirty frail older (age, 70 +/- 5 yr) obese (body mass index, 37 +/- 5 kg.m) adults were randomly assigned to 6 months of diet/behavioral therapy (diet group, n = 15) or diet or behavioral therapy plus exercise that incorporated progressive resistance training (PRT; diet + exercise group; n = 15). Body composition was assessed using dual-energy x-ray absorptiometry, and muscle strength was assessed using one-repetition maximum. The volume of upper extremity (UE) and lower extremity (LE) exercise training was determined by multiplying the average number of repetitions performed by the average weight lifted during the first three exercise sessions and during the last three exercise sessions of the study. RESULTS: The diet and the diet + exercise groups had similar (P > 0.05) decreases in weight (10.7 +/- 4.5 vs 9.7 +/- 4.0 kg) and fat mass (6.8 +/- 3.7 vs 7.7 +/- 2.9 kg). However, the diet + exercise group lost less fat-free mass (FFM; 1.8 +/- 1.5 vs 3.5 +/- 2.1 kg), LE lean mass (0.9 +/- 0.8 vs 2.0 +/- 0.9 kg), and UE lean mass (0.1 +/- 0.2 vs 0.2 +/- 0.2 kg) than the diet group (P < r =" 0.64-0.84;" style="font-weight: bold;">
CONCLUSION: Exercise added to diet reduces muscle mass loss during voluntary weight loss and increases muscle strength in frail obese older adults. Regular exercise that incorporates PRT (progressive resistance training) should be used to attenuate muscle mass loss in frail obese older adults on weight-loss therapy.
My Notes: See my above comments!
Inflammatory Response to a High-fat, Low-carbohydrate Weight Loss Diet: Effect of Antioxidants.
Peairs AT, Rankin JW. 1Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, Virginia, USA. The objective of this study was to test the hypothesis that the inflammatory response to a high-fat, low-carbohydrate weight loss diet (HF) we previously observed was due to oxidative stress. Nineteen overweight subjects (BMI > 27 kg/m(2)) were randomly assigned to either an antioxidant supplement (AS) (1 g vitamin C/800 IU vitamin E) or a placebo (P) group and provided with a HF for 7 days. Fasted pre- and post serum samples were measured for markers of inflammation (C-reactive protein (CRP), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1)), oxygen radical absorbance capacity (ORAC), and glucose, whereas urine was measured for oxidative stress (8-epi-prostaglandin-F(2alpha) (8-epi)). HF resulted in significant reductions in weight (-3.2%), glucose (-18.7%), and MCP-1 (-15%) (all P < p =" 0.076)." r =" -0.501)," r =" -0.863)," r =" -0.546)" style="font-weight: bold;">
Conclusion: Longer term diet-controlled studies are necessary to further explore the trend for a differential response in CRP (C-reactive protein) with antioxidant supplementation.