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If you watched the ABC show Catalyst about fasting, you may remember the husband who went on the 5:2 calorie restricted fast, lost the most weight but also lost the most, lean body mass. Healthy weight loss involves losing body fat while preserving as much muscle as possible, so how can we prevent muscle loss while fasting to successfully lose weight, and why does it matter?

I’ve recently joined an over 50’s gym in Sydney’s Northern Beaches. Each gym, (they are called Club Active and there are 8 in Australia so far) is run by exercise physiologists, who design programs specifically for each member. At this stage of life, our reason to exercise is quite different to the days when a flat stomach and toned arms were all that mattered. Here in this non-intimidating environment, everyone has their physical limitations, however regardless of whether it’s osteoporosis, osteoarthritis, shoulder, knee, or hip injury, and/or being overweight, the universal recommendation is to build strength.

Sarcopenia is the name given to age-related, involuntary loss of skeletal muscle mass and strength. It starts at around 40 and is most rapid in those aged between 60 and 70 where muscle loss can be between 3 to 8 percent each year. The consequences are worse than no longer being able to shake the queen-sized doona back onto the bed after changing its cover. Loss of muscle slows the metabolism, reduces stamina, weakens bones, effects balance and mobility and ultimately leads to an increased risk of falls, and fractures.

Never is the phrase use it or lose more accurate: If we don‘t work to maintain muscular strength, the aging process is dramatically accelerated.

To be perfectly honest, I’ve never liked gyms but, and as I say to many of the members, this is a case of just “suck it up and do it”. Saggy tuck shop lady arms, and a flabby tummy fail to compare with the threat of long-term disability and loss of mobility in life. I want to be able to walk, climb mountains, carry my groceries, pick up grandchildren and puppy dogs. I want to live life to the fullest for as long as possible and I don’t want my body to let me down.

Actually, if I don’t do the strength training, I will let my body down.

Strength or resistance training improves muscle size, strength, and tone and it strengthen bones, ligaments, and tendons.

What about fasting and muscle loss?

If you’re tempted to join me in Lighten Up Spring, which launches on Friday 2nd September, your diet will include two, non-consecutive 500 calorie-restricted fasting days, or 600 for men. Each week, you’re supplied with easy-to-follow recipes for those fasting days, and on the remaining days, combined with other healthy eating challenges, I encourage you to include protein with each meal: Lean meat, turkey, chicken, fish, eggs, low fat milk and yoghurt, beans and legumes are all good sources of protein. Protein intake is critical when it comes to preserving or gaining muscle while losing fat, it’s also a good dietary hack. Protein provides satiety and helps you feel full for longer, theoretically diminishing the craving to eat between meals.

Resistance and strength training

Provided you eat adequate protein, there’s no need to worry about losing muscle with short-term intermittent fasting. Add some strength/resistance training to your program and your chances of increasing lean body mass are increased.

Strength training is essential when you are fasting and when you’re not!

Why 5:2 intermittent fasting can be more successful than traditional diets?

Let’s face it, we’re older, we’ve been around the block for a long time and habits are hard to break. Not only that but we’ve probably also established so many weekly social engagements that 7-days dietary restriction is pretty hard to stick to.

  • It’s easier to find 2 days in the week to be abstemious, and it’s easier to stay on track when you know you don’t have to restrict your intake the following day.
  • We don’t typically make up for the calories we missed while fasting; this leads to built-in calorie restriction.
  • When we cut out carbohydrate on fasting days, the liver’s glycogen stores are usually depleted within the first 24 hours, leading to the mobilisation of fatty acids from fat stores for use as energy.


Everyone over 50 should incorporate strength/resistance training into their exercise routine whether they are fasting or not. Aim to train 3 times a week and consider booking an appointment with an exercise physiologist to devise a program specifically for you.

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