Mixed
Maintaining a body weight 10% below usual increases skeletal muscle work efficiency and shifts fuel utilization toward fatty acids at low exercise intensities (10-25 W) by decreasing glycolytic enzyme activity (PFK) relative to oxidative capacity, without changing mitochondrial density or fiber type.
When you lose weight, your body becomes more efficient at moving, especially during light activities like walking or slow cycling. This means you burn fewer calories for the same amount of light activity than you did before. To maintain your new weight, you may need to be mindful of your diet and ensure you are getting enough physical activity, as your body's 'default' efficiency has increased to conserve energy.
Maintenance of a reduced body weight was associated with an approximate 15% increase in skeletal muscle work efficiency during exercise to generate 10 W (P < 0.001) and 25 W of power (P < 0.01), and with a significant decline in RER only at low workloads... The maintenance of a 10% reduced body weight was associated with significant declines in glycolytic (phosphofructokinase, PFK) enzyme activity and, in particular, in the ratio of glycolytic to oxidative (cytochrome c oxidase, COX) enzyme activity without significant changes in the activities of enzymes relevant to mitochondrial density... or in skeletal muscle fiber type
Why this rating
Controlled inpatient study with rigorous biochemical and ergometric measurements, though small sample size for weight gain.
Source
Effects of experimental weight perturbation on skeletal muscle work efficiency, fuel utilization, and biochemistry in human subjects
Rochelle Goldsmith et al. · American Journal of Physiology-Regulatory, Integrative and Comparative Physiology · 2009
DOI 10.1152/ajpregu.00053.2009
Related findings · Mixed
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