Lose fat, not muscle for long term weight management

When we lose weight, we typically lose a combination of fat and muscle. When we lose weight, we are eating less calories than our body needs and therefore creating a calorie deficit. To compensate for this reduced energy coming in from food, the body breaks down both fat and muscle to make up the difference. 

But why doesn’t the bodybreak down the fat and leave the muscle where it is?  That would be so much more convenient wouldn’t it? Well muscle tissue requires a lot of energy to maintain, so when the body is in a calorie deficit, it is trying to conserve energy and therefore offloads some of those energy hungry muscles and creates some well-needed energy in the process (which is a handy skill if you ever get lost in the bush for a couple of weeks!)  This is particularly true if you are losing weight rapidly or not consuming enough protein in your diet to support muscle growth and maintenance.

However, it is important to note that losing muscle is not an inevitable consequence of weight loss. With a bit of planning and maybe even some individualised advice, you can slow down or even halt the loss of muscle while losing weight. Some important factors to consider are:

  • Total protein intake. Protein requirements can vary widely depending on the type, duration, and frequency of your exercise. If you are weightlifting with the intention of ‘bulking-up’ then you may need as much as 2g of protein per kg of body weight. If you are trying to bulk up, then you can’t lose weight at the same time. If like most people, you are doing more cardio and muscle strengthening work, your requirements could be between 0.8 – 1.5g per kg of body weight. So for a 90kg person, this would mean aiming for around 90g of protein a day.


  • Protein is a source of calories too. Protein has the same calories per gram as carbs so it definitely isn’t a matter of ‘the more protein the better’. A cheeky protein shake after a workout or between meals when you don’t need it, may be what’s getting in the way of your weight loss. 
  • The spread of protein through the day. The body can only utilise around 20-25g of protein at a meal. So, when you have anything more than around 100g of meat, the excess protein will be repackaged (by the liver) into fat and sugar to be used for energy or to be stored (depending on if you just ate more or less energy than your body needed). Your muscles will get access to more protein if you split your daily protein needs into smaller and more frequent meals and snacks.
  • Resistance training to minimise muscle loss. To reduce the natural muscle loss during weight loss, some research has shown that with regular resistance training, the loss of muscle mass can be minimised. This means you can hang onto more of your muscles which will keep your metabolism as high as possible. The higher your metabolism, the easier it will be to get the weight off and keep it off!


So be protein smart and work out the best approach for you and your needs. If you need some extra help, get in touch with our dietitian who can advise you on your protein daily intake


Anna D’Arcy, Accredited Practising Dietitian, My Nutrition Clinic
March 02, 2023
Tags: Exercise