CHB 2.2.4: Loose Muscle, Gain Fat?

Data on Muscle Loss and Weight Gain

Next to an increased risk for developing/aggravating conditions of MSK, lifestyle changes as observed during COVID-19 confinements, i.e. physical inactivity and poor nutritional habits (Ammar et al., 2020), have the potential to result in both muscle loss and weight gain through fat accumulation. Indeed, even in young adults, periods of less PA measured by reductions in step counts as reported during COVID-19 confinements (Sun et al., 2020) have been shown to result in rapid losses of muscle mass and physical function (Breen et al., 2013) promoting fat accumulation and weight gain for many (Ammar et al., 2020; Kirwan et al., 2020). With strong evidence, the age-related loss in muscle mass, i.e. sarcopenia, has been identified as a naturally occurring gradual process that can be decelerated through physical activity and exercise as well as nutritional habits, e.g. consuming sufficient amounts of protein (Kirwan et al., 2020). In fact, engagement in muscle strengthening activities has been shown to benefit muscle size and force development in older adults (Agaard et al., 2007). On the downside, periods of physical inactivity and increased sedentarism are suggested to accelerate the age-related muscle loss (English & Paddon-Jones, 2010). These effects may be amplified even further through poor dietary behavior that inherently reduce in protein intake as observed during COVID-19 confinements. Considering muscle mass and strength representing strong predictors of health and longevity (Li et al., 2018), these effects are concerning for individual’s health as they entail long-term health risks that will be discussed below. However, the actual magnitude of effects is yet unclear and will need to be identified in future research.