This is a brief article summary from the MASS Research Review article titled ‘The Role of Physical Activity in Appetite and Weight Control.’ To read the full article and get more details on the topic of weight and appetite control via physical activity, subscribe to MASS here.
Many people are familiar with the idea of increasing physical activity in order to increase caloric expenditure to regulate body weight. Another interesting and less familiar way adding physical activity can affect appetite is by regulating satiety signals. In this MASS Research Review article titled ‘The Role of Physical Activity in Appetite and Weight Control,’ Dr. Eric Helms reviews a study by Beaulieu et. al. that observes how increased physical activity affects appetite and weight regulation. Let’s first preview the key points listed in this research review article and then review the interpretations of the research in question.
‘The Role of Physical Activity in Appetite and Weight Control’ Article Key Points:
- “Physical activity does more than just increase total energy expenditure. When activity is low, appetite is dysregulated, resulting in excess food intake and weight gain. Higher levels of activity seem to increase appetite control.”
- “The combination of being too high in body fat and also being physically inactive may further dysregulate appetite and satiety signaling, making weight loss efforts even more difficult.”
- “Physical activity and exercise may only be effective to a point for the goal of weight loss. At very high levels of physical activity, additional increases may not result in an increase in total energy expenditure, but rather a downregulation of energy expended from other components of total energy expenditure and no change in net expenditure.”
Physical Activity vs. Exercise
Before summarizing the research listed in this article, it’s important to define and differentiate the differences between physical activity and exercise. Physical activity is defined by the World Health Organization simply as “all movement.” This can include playing sports, walking the dog, gardening, cycling, play and recreational activities. Exercise is otherwise defined in this Public Health Reports article as “a subset of physical activity that is planned, structured, and repetitive and has as an objective – the improvement or maintenance of physical fitness.” The article reviewed in this blog uses the broader term of physical activity as a means toward appetite control and showcases how simply being more active (and not necessarily only engaging in a dedicated exercise program) can also be beneficial to your health and weight management.
How Physical Activity Affects Appetite Control
Our bodies have regulatory mechanisms in place that work to control our body weight in an attempt to avoid extreme starvation and obesity. When physical activity levels are too low, these mechanisms work suboptimally and can become disrupted. Figure 2 in the MASS Research Review article shows that with high physical activity levels there was an inverse relationship between body fat and meal size. This meant that those with high physical activity levels and high body fat levels had lower meal sizes and vice versa. Figure 2 also notes that there is “no significant inverse relationship between body fat and meal size at low-moderate levels of physical activity.” The research review also mentioned that while increased physical activity was associated with a greater desire to eat, the higher physical activity levels were also associated with increased satiety in response to meals leading to less overconsumption of food. With low levels of physical activity, appetite control becomes dysregulated and energy consumption fails to match energy expenditure. Furthermore, higher body fat levels on top of low physical activity levels lead to even more appetite dysregulation and weight gain.
Another point to extract from this research review is the J-shaped relationship between physical activity and appetite control. At lower levels of physical activity, energy intake tends to be higher due to appetite dysregulation. As physical activity increases, appetite regulation improves leading to decreased consumption. As physical activity increases even more, energy intake increases as well with this coupling maintaining an optimal balance between the two (intake and expenditure), preventing overconsumption and weight gain. With that in mind, another energy expenditure model is presented in this research article titled the ‘Constrained Vs. Additive Model of Energy Expenditure.’ Put briefly, this model explains that energy expenditure will only increase with an increase in physical activity up to a certain point. Total energy expenditure may become “constrained” or restricted even though physical activity is increased. This was examined in hunter-gatherer societies that had very high physical activity levels that did not match their predicted total daily energy expenditure levels. One key takeaway from this information is to not get overzealous with adding physical activity into your daily routine. Most people are not getting enough physical activity currently, however, make an effort to add physical activity into your day in a practical and realistic way as adding more than necessary may not add any additional benefits anyway.
Why is this Important?
Traditionally, obesity and weight management programs have often only viewed weight control through the “eat less, move more” paradigm. While fat loss is a function of calories in vs. calories out, other mechanisms can be included to aid in weight management that doesn’t involve extreme restriction or extreme exercise protocols. Adding in more physical activity into your daily life can increase energy expenditure and regulate appetite when managing weight. In the MASS Research Review Article, Dr. Eric Helms stresses the importance of implementing physical activity into your daily life. Bike riding, walking to stores or parks, hiking, bowling, etc. are all ways to increase your daily physical activity even in addition to a traditional resistance or cardiovascular exercise program. The WHO states that “inactivity is one of the leading risk factors for noncommunicable diseases and death worldwide. It increases the risk of cancer, heart disease, stroke and diabetes by 20–30%. It is estimated that 4-5 million deaths per year could be averted if the global population was more active.” Being more physically active will create a multi-factorial impact on your health, well-being, and longevity.
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