Rapid weight loss can lead to significant loss of muscle mass as well as fat, so how can this be prevented?
Muscle is an important factor in determining our metabolic rate, and is more metabolically active than fat, which means it burns more calories.
When we diet to lose weight, we create a calorie deficit, where our bodies do not get enough energy from food, causing them to break down fat and muscle tissue for energy.
A decrease in calorie-burning muscle mass slows down our metabolism, thus slowing down our rate of rapid weight loss, affecting our ability to maintain our weight in the long term.
How to Check for Losing Too Much Muscle Mass
There are 3 scientifically backed signs that you may be losing too much muscle mass when dieting:
1. Losing weight at a higher than expected rate each week
Losing a lot of weight quickly is one of the early signs that your diet is too aggressive, and you are losing too much muscle.
Rapid weight loss (more than 1 kg per week) results in greater loss of muscle mass than slow weight loss, which preserves muscle mass better and often has the added benefit of increased loss of fat mass.
2. Feeling tired
Feeling tired, lethargic, and having difficulty completing physical activities is a strong sign that you are rapidly losing muscle mass.
Research shows that low muscle mass can negatively impact your body's physical performance.
3. Mood swings
Mood swings and feelings of anxiety, stress, or depression may also be signs of muscle loss.
Low levels of muscle mass have been shown to negatively impact mental health and mood, due to the relationship between low muscle mass and neurotransmitter proteins, which help regulate mood and feelings of well-being.
How to maintain muscle mass while losing weight?
There are 3 steps you can take to maintain muscle mass when following a calorie-restricted diet to lose weight:
1. Incorporate strength training into your workout plan.
Strength-building exercises are a surefire way to help prevent muscle loss.
An analysis of studies in obese older adults found that resistance training was able to prevent nearly 100% of muscle loss due to calorie restriction.
Relying on diet alone to lose weight will result in reduced muscle mass along with body fat, which will slow down your metabolism.
Therefore, appropriate exercise should be incorporated into your weight loss plan, to maintain your muscle mass stores.
2. Eat more protein
Protein-rich foods play a key role in building and maintaining muscle mass, but research also shows that these foods help prevent muscle loss on a calorie-restricted diet.
This does not mean just eating foods that contain protein, as meals must be balanced and include a source of protein, whole grains, carbohydrates and healthy fats to meet our nutritional needs.
3. Slow down your weight loss plan
When we change our diet to lose weight, we push our body out of its comfort zone and trigger the survival response. The body then resists weight loss, leading to many physiological hunger responses.
So, a gradual, slow and steady approach to weight loss should be followed, which prevents our bodies from activating defense mechanisms when we are trying to lose weight.
Report by Nick Fuller, Charles Perkins Centre Research Programme Leader, University of Sydney.