How To Maximize Fat Loss and Minimize Muscle Loss

author:  Kelly Gill, MS, RD, CSSD, LD


When you lose weight, it’s inevitable that you will lose muscle along with fat.  However, there is an effective way to maximize the amount of fat loss and minimize the amount of muscle loss!


A calorie deficit is required for weight loss to result.  That means, to lose weight, you have to eat fewer calories than you burn.  In theory, it doesn’t matter where those calories come from.  For example, your calories could come from candy and, as long as those calories were fewer than the amount of calories your body burned, you would lose weight.  Of course, getting all your calories from candy would be to the detriment of your overall health, but you would be skinnier.  Unfortunately though, you would probably lose quite a bit of muscle mass in addition to fat loss, and that is never ideal.


Besides the appearance of muscles (I know, they look so nice, don’t they?!), another advantage of maintaining muscle mass is for your metabolism.  Muscles burn more calories than fat.  So, when you are losing weight, you want to lose as much fat as possible and as little muscle as possible.  That can actually help you continue to lose weight!!  Of course, appearance and metabolism aren’t the only benefits of muscles.  Muscles protect our joints, reducing the risk for injury.  Also, they make us stronger and, ultimately, can improve our quality of life.


Now, preserving muscle mass and building muscle mass are two separate things.  Building muscle requires the presence of a calorie surplus.  You can’t be in a calorie surplus and expect to lose fat.  In fact, it is for that reason that bodybuilders train in two phases.  They have a building phase and a cutting phase.  During the building phase, they eat more calories to build muscle.  Then later, in the cutting phase, they eat fewer calories to burn fat.  My aim today is to describe how to lose weight from fat while maintaining lean body mass, similar to a body builder’s cutting phase, because, albeit to a much less extreme, that is essentially what you have to do!


So, how can you maximize fat loss while minimizing muscle loss?

  1. Eat enough protein
  2. Lose weight slowly
  3. Incorporate resistance training into your workout routine
  4. Stay hydrated
  5. Ensure adequate sleep
  6. Manage stress


1. Eat enough protein

Protein is the most satiating (makes you feel full and satisfied) macro-nutrient, plus it takes more energy to metabolize.  Not to mention, protein is used by the body for tissue repair and maintenance.  It stands to reason, that increasing protein intake would be necessary to help maintain muscle, which is made of tissue.

So, how much is the right amount of protein?

Naturally, that will vary from person to person, but there is a substantial body of research that demonstrates the magic number should be between 1.6 g/kg/day and 2.4 g/kg/day.  This amounts to 109-164 g/day for 150 lb person.  Now, fat doesn’t have the same metabolic needs as lean mass.  Therefore, if you have a lot of excess body fat, then you really shouldn’t use your total weight to calculate your protein needs.  A registered dietitian can help you figure out the right amount for you.

Keep in mind, for weight loss to occur you must be in a calorie deficit – you must eat fewer calories than your body burns.  As such, all of the studies I am referring to were conducted during a hypo-caloric state.  This higher protein intake in the presence of reduced calories also appears to help maintain metabolic rate, which is an added benefit!  While reducing calories usually results in a slower metabolism, increasing protein can help offset that phenomenon.


2. Lose weight slowly

In studies where subjects lost weight slowly, they were better able to preserve their lean mass.  This is especially true with leaner subjects.  On the other hand, the more body fat you have, the more rapid you may lose weight without it being to your detriment.  Since, greater initial weight loss is associated with greater long-term success (in other words, the more weight you lose when you start, the more likely you are to continue to lose and/or sustain the weight loss), if you have a lot of weight to lose, it can be beneficial to be more aggressive with your calorie restriction as you start.  However, as you slim down, the weight loss will need to slow down in order to ensure preservation of lean body mass.  Of course, it has been my experience that this tends to happen, naturally, anyway.


3. Incorporate resistance training into your workout routine

Resistance or weight bearing exercise uses your muscles.  Thanks to the adaptation process, regular muscle contraction tells your body that it needs to build bigger and stronger muscles for future demand.  On the other hand, a sedentary muscle is fair game to provide fuel for the body during a calorie deficit.  In other words, your body will readily break down an untrained muscle for fuel in the presence of a calorie deficit, while it will preserve a trained muscle and turn to using more fat stores for fuel, instead, knowing that the trained muscle is needed for future use.

In one study, some untrained subjects actually showed an increase in lean body mass when they started a resistance training program, despite following a hypo-caloric diet and losing fat.  Although, the muscle gain was minimal.


4. Stay Hydrated

A well hydrated body is a well functioning body.  On the contrast, when you are dehydrated, nothing works well.  Dehydration causes a strain on every system in the body.  Specifically, hydration is associated with a better metabolism and better appetite control.  Hydration optimizes weight loss and improves exercise performance.  Therefore, it is essential to maintain proper hydration to maximize fat loss and minimize muscle loss when you are losing weight.


5. Ensure adequate sleep

If you haven’t yet read my blog on sleep, you should.  One of the consequences of inadequate sleep is undesirable body composition – this usually means high fat, lower muscle mass.  This is seen with multiple studies.


6. Manage stress

You may have heard about a hormone called cortisol.  It is part of the fight or flight response to stress.  As such, it increases in circulation under times of stress (physical and emotional stress).  One of the unfortunate effects of cortisol is to cause protein to be converted to glucose – the fuel needed for fight or flight.  Also, cortisol reduces protein synthesis (the process of making protein) and stops tissue growth (remember, muscles are made of tissue, so this is not good for maintaining muscle mass).  So, with increased cortisol and other stress hormones, you can expect to see more muscle breakdown, especially in the case of a calorie deficit.

I realize we all have stress.  It is unreasonable to try to eliminate stress from your life.  However, how you handle that stress is critical.



To lose weight, you do have to eat fewer calories than you burn.  However, if you don’t take care, this weight loss can be at the detriment of your muscle mass.  By following the above suggestions, you are more likely to preserve your muscle mass and maximize your metabolic rate – which helps with continued fat loss.

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