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Top 5 Tips for Maintaining Muscle Mass Whilst Dieting

Resistance training
Set your deficit
Protein target split across 4 meals / 4 hours apart
Measure progress, adjust deficit if needed
Consistently sleep at least 7 hours a night

Minimising muscle loss during a diet

The very simple answer is resistance training and protein at each meal. If you are not lean, don’t want to track food intake closely and your goal is to drop some body fat whilst minimising muscle loss, this is probably fine as a guide.

In nearly all cases of dieting and weight loss, the goal is actually to reduce body fat mass whilst maintaining as much muscle mass as possible. The loss of some muscle and strength during a diet is thought of as a reality of having a reduced amount of energy available for a sustained amount of time.

How to predict your rate of weight loss
A fairly consistent recommendation is to aim for a body weight reduction of about 0.5-1% per week during a diet, to try and minimise any potential muscle and strength loss.(1) The larger the deficit being the predictor of more muscle loss. (3). There is another school of thought that you may consider dieting as hard and fast as possible, get down to goal weight / goal leanness faster, then finish the diet earlier in order to be able to then start training again at maintenance energy levels.

First you need to have a good idea of your maintenance Calories. You could use an online calculator or track your food/drink intake and body weight for a couple of weeks. If your weight is fairly stable, you will have your average maintenance Calories.

The 3500 Calorie rule, as it’s known, is more of a general guideline which estimates that to lose 1 pound of fat (about 0.5kg) you need to a Calorie deficit of about 3500 Calories. So if you were 100kg and were aiming to lose 0.5% per week, you would estimate that you need to average a weekly deficit of about 3500 Calories. It is not an exact science though and may need to be altered over time depending on progress. (2).

The website of the USA National Institute of Diabetes and Digestive and Kidney Diseases hosts a “Body Weight Planner” which is an interesting resource for looking at estimated rates of weight loss and could give you some insight and reasonable expectations about you goal and the length of your diet. (https://www.niddk.nih.gov/bwp)

Training

It’s a bit of a “use it or lose it” story with muscle. Continuing a resistance training program whilst dieting is more important than nutrition when it comes to minimising reductions in muscle and strength.(3)

Rates of weight loss and protein in studies

A major consideration is going to be your starting point.

In a study of overweight young men who were not regularly participating in resistance training, the study gave a great insight into “newbie” gains and gaining muscle while losing fat. Two groups were both set a 40% Calorie reduction for 4 weeks. One group consumed 1.2 grams of protein / kg body weight / day and the other group 2.4 grams of protein / kg body weight / day. Both groups lost the same amount of body weight, the lower protein group maintained lean body mass and the high protein group, despite a 40% reduction in energy intake, actually increased lean body mass. Also of note is the difference in average protein content per meal in the groups. The low protein group averaged 0.23 grams / kg body weight / meal whereas the high protein group averaged 0.48 grams of protein / kg body weight / meal.(4) The amount of the amino acid leucine per meal is a driver of muscle protein synthesis (muscle growth) and it is estimated that around 30-40 grams of protein per meal would be needed to reach a leucine threshold high enough to stimulate muscle protein synthesis (1).

In a study of track and field athletes, two groups were assigned either a 750 Calorie/day deficit (24% deficit) or a 300 Calorie/day deficit. Both groups consumed 2.1 grams of protein / kg body weight / day. After the four weeks of dieting, the larger deficit group lost 2.2kg body weight on average, with 0.5 kg being fat free mass (body weight - bones and fat). The smaller deficit group lost 0.4kg body weight on average with 0.2kg being fat free mass. So with a larger deficit, a little more fat free mass was lost but significantly more fat mass. What is really interesting about this study is that athletes with a body fat percentage of more than 10% at the start of the study were able to preserve more fat free mass. (5) In practicality, except in very specific sports and physique competitions, it’s unlikely many people would (or should) try to diet into single figure body fat percentages anyway.

An interesting study of young athletes actually compared rates of weight loss, with one group targeting a reduction of 0.7% bodyweight per week and another above the mentioned guidelines of 1.4% bodyweight per week. The slower group had a 19% Calorie deficit and the faster group 30%. The slower group consumed 1.6 grams of protein / kg body weight / day and the faster 1.4 grams of protein / kg body weight / day. Both groups trained 4x per week. Both groups dieted to lose about 5.5% bodyweight. The fast group took 5.3 weeks on average and the slow group 8.5 weeks. The slow group actually increased lean body mass a little whilst losing fat and the fast group lost a tiny amount of lean body mass. (6) What would be interesting would be if this study had the fast group then consume their new maintenance Calories and continue training up until the 8.5 week mark to then compare the two methods. Would the fast group have regained that minimal loss and potentially gained some more muscle in those 3 weeks? There is also a difference, although slight, in protein intake and in reality, whilst the fast group was targeting 1.4% weight loss per week, they actually average 1%.

In a study of young athletes who were regularly resistance training (4-5x per week) they were seperated into a lower protein group 1 grams of protein / kg body weight / day and a high protein group 2.3 grams of protein / kg body weight / day and a high. Both groups had a 40% reduction in energy intake for 2 weeks and lost a similar amount of body weight. The low protein group however lost about 5x more lean body mass than the high protein group on average. (7)

Those studies are some “food” for thought when considering the size of your intended deficit.

Protein

We’ve already touched on protein a little and the studies above have some interesting data on protein targets across a day and at each meal.

If dieting, the amount of protein consumed should be higher than someone focussing on muscle gain or re-comp. This is due to the Calorie restriction during a diet meaning that less carbs are available for energy and some protein may be broken down and used in place (3). How high this protein intake should be will depend on the individual circumstances. Looking at the above studies, 1.2 grams / kg body weight / day was enough to preserve lean body mass in untrained overweight males when combining diet with a new resistance training program. However under the same conditions, 2.4 grams / kg / day was actually better.

In athletic and training groups, the range of 1.6 - 2.3 grams of protein / kg body weight / day performed well in slow and faster diets in relation to the preservation of muscle.

A systematic review of protein intakes for athletes and resistance trained individuals gives a guideline of 2.3 - 3.1 grams of protein / kg body weight / day scaled up with the size of the energy deficit and leanness of the individual. (8)

Fats and Carbs

After choosing the size of the deficit you are going to aim for and your protein intake target, whatever Calories you have left to budget will go to carbs and fats. You probably don’t want to go below 20-25% of total Calories from fat, then the rest would probably be best spent on carbs as fuel for training. Remembering that training is most important for muscle retention. However personal preference really can determine these ratios. (3).

Sleep

Sleep and recovery will be important, not only so you feel as good as possible whilst dieting and can train well. It could also play a role in how much weight loss in a diet is fat and how much is muscle. A study of overweight and sedentary adults had groups with a sleep opportunity of 5.5 hours or 8.5 hours per night. The short sleep time resulted in 60% more weight loss from fat free mass compared to the longer sleep group. In the short sleep group, 25% of weight loss was fat mass, whilst in the longer sleep group 56% of weight loss was fat mass. These groups were not resistance training, however the results would certainly encourage giving yourself the opportunity to sleep longer. (9).

Summary and Recommendations

Be very clear with your goals, expectations, starting point, length of diet and best practice recommendations.
Have a resistance training program and stick to it.
Know or calculate predicted maintenance Calories.
Set your deficit based on step 1 and strongly consider the 0.5-1% weight loss guideline.
Set your protein between 1.6 - 3.1 grams / kg body weight / day depending your circumstances in step 1.
Spread protein intake out across your meals, with probably at least 4 meals and close to 30 grams of protein per meal as minimum.
Calculate your remaining Calories and distribute to fats and carbs, not going under about 20-25% of total Calories from fats (or about 0.5 grams / kg body weight / day).
Monitor progress with a number of methods, scale weight, hip and waist measurements, progress photos. Also monitor training performance, mood, sleep and take all into account regularly. You may need to change your plan at some point depending on all of these variables.
When happy with your body composition, calculate your maintenance Calories based of your new weight and start consuming that amount of energy whilst continuing to monitor the same measures of progress.

To learn more about how a nutrition coach can help you maintain your lean body mass whilst dieting, contact us today.