It's easy to gain weight, but it's not eat to gain muscle mass without a lot of fat gain. Plan your diet and training for weight gain without too much fat!

Gain healthy weight

There are many reasons why a person may require weight gain due to being underweight. Genetics may play a major part in keeping a person lean. Some medical conditions may alter the way food is digested or have an effect on a person’s food intake. So the first port of call for any underweight individual would be to visit their doctor to rule out any hormonal imbalances and also medical conditions that may lead to inadequate absorption of nutrients.

Other problems like social pressures may contribute to being underweight, an example would be females who desire to be thin. A working environment which is very physical, yet has no time for meal breaks. Students, who might be constantly studying for exams may have a problem with constantly missing their meal times. Emotional problems may cause difficulties with food intake in that during periods of emotional crisis appetite may be increased due to comfort eating and in some people the opposite may occur with appetite being depressed, often for long periods. Another problem may be economic in which an individual may not be able to spend much money on foods due to having to make money available to meet other financial commitments.

Having a purpose for gaining weight.

Having an important reason for gaining bodyweight may give the drive required for weight gain.

One reason may be for an increased physical appearance for attracting partners. Self esteem may be another reason. The athlete who may want to increase power, strength, speed or muscle mass may also benefit for weight gain.

Whatever the reason that a person may have for gaining weight remember that weight gain may compromise speed if that is a main goal from weight gain.

Calorific Intake

This subject is a very important factor in weight gain and depends on a number of factors, age, bodyweight, sex, resting energy expenditure (REE), the thermic effect of feeding (TEF) and also a persons physical activity levels (PA).

REE is the amount of calories required by the body for a day at rest to stay alive (also known as BMR or basal metabolic rate). Most of the body's energy, about 60-70%, goes to supporting the ongoing metabolic work of the body's cells. This includes such activities as heart beat, respiration and maintaining body temperature. There are many formulas used in calculating REE or BMR depending on medical conditions, age, obesity and other factors. One of the most frequently used formulas for predicted energy expenditure is the Harris Benedict formula.

Harris-Benedict Equations (calories/day):
Male: (66.5 + 13.8 X weight) + (5.0 X height) - (6.8 X age)
Female: (665.1 + 9.6 X weight) + (1.8 X height) - (4.7 X age)
(weight in kilograms, height in centimetres, age in years)

TEF or Thermic effect of feeding; represents the increase of energy expenditure associated with digesting, absorbing and storing food. In most individuals it accounts for approx 10% of daily energy expenditure.

TEA or Thermic effect of activity; is the amount of energy expended in all non resting daily activities be they occupational, recreational or domestic, and contributes 20-30% to the body’s total energy output.

An easy way to calculate your calories required to maintain your bodyweight is to use Muscle&Strength's BMR Calculator.

We now know by use of the calculator above what calories we require per day to maintain our bodyweight. Our goal though is to “increase” our bodyweight, not maintaining it, but without the common gaining of large increases of bodyfat. The only way we can do this is by increasing bodyweight through resistance training, which in turn increases our muscle tissue. But to do this we have to increase our calorie intake.

Our muscle tissue consists of approx 70% water, 22% protein, and the remainder is fat, carbohydrates and minerals. By taking away the water content of the muscle which has no calorific value, the total caloric value of one pound of muscle tissue is only approx 700-800 cal. We already know that to add muscle tissue we have to add more calories than our body burns off to synthesise new muscle tissue.

Studies have shown that between 5 to 8 calories are required to support an additional 1 gram of new tissue during growth. With the recommended amount of weight gain per week of 1 lb (1 lb = 454 grams). This gives us an approximate requirement of 2300 – 3500 extra calories would be required per week. Which would give us a requirement of an extra 400 – 500 extra calories per day, above our normal calorific maintenance level.

Ok; we now know that we require extra calories, but where do we get them from? We can have extra fast food that would increase calories. This would also increase body fat; we have to increase the foods that the body requires if we are going to embark on a resistance training program to increase our lean body mass and also our total bodyweight. The foods that are required are proteins, carbohydrates and essential fats but how much?

Nutrient Intake For Strength Trained Athletes

Energy Carbohydrates Protein Fat
30-60 calories per kilogram of body weight (needs vary depending on the specific sport) 6-10 grams per kilogram of body weight. 1.4-1.7 grams per kilogram of body weight At least 1.0 gram per kilogram of body weight and enough to meet energy demands.

Note: 1 kilogram = 2.2 lbs.


Protein Foods: Lean meats, Fish, Poultry, Eggs, Milk, Cheese, Yogurt, Peanut Butter, Beans, Tofu, Lentils, and other Legumes, Grains, including bread and pastas, Nuts, and Seeds

Protein Functions: Proteins that we eat are digested into amino acids and these are joined along side other amino acids produced by the body to constitute the amino acid pool. Tissues take the amino acids from the pool to synthesise specific proteins the body needs for muscle, hair, nails, hormones, enzymes etc. Proteins maintain fluid balance and buffer both acid and alkaline environments to maintain blood pH, transporter of vitamins and minerals, oxygen. Provide a source of carbon for energy yielding reactions by amino acid conversion to glucose and metabolised to provide ATP, while others can be stored as fat.


Carbohydrate Foods: Rice, Pasta, Bread, Potatoes, Cereals, Fruits, Vegetables, Beans, Pulses, Yogurt, Milk.

Carbohydrate Functions: To provide energy and muscular fuel for body strength and building muscle. Carbohydrates are converted to stored energy as liver and muscle glycogen, sugars and starch acts as the perfect fuel to enable you to carry out your physical activities efficiently and effectively. Fiber is important in keeping bowel function going smooth. Carbohydrates aid in regulating blood glucose.


Fat Foods: Nuts, Nut oils, flaxseeds, avocados, sunflower, rapeseed and olive oil and olive oil spreads, fish and fish oils.

Fat Functions: Essential fats (EFAs) are necessary fats that us as humans cannot synthesise and must be obtained though our diet. EFAs are long chain polyunsaturated fatty acids derived from linolenic, linoleic, and oleic acids. EFAs support the cardiovascular, reproductive, immune, and nervous systems.

The human body needs EFAs to manufacture and repair cell membranes, enabling the cells to obtain optimum nutrition and expel harmful waste products. An important function of EFAs is the production of prostaglandins, which regulate body functions such as heart rate, blood pressure, blood clotting, fertility, conception and play a large role of immune function by regulating inflammation and encouraging the body to fight infection.

Dietary Supplementation

For some people dietary supplementation is necessary to increase calorie intakes due to some restraints with regard to obtaining nutrient dense solid foods. Protein powders, carbohydrate powders like Maltodextrins or Dextrose, and essential fats, are all available to supplement a nutrition plan, but may be costly.

Creatine Supplementation.

Using creatine can increase bodyweight and can improve strength with high intensity resistance exercises with short term recovery. Weight gain at the start of using the supplement will be water weight, but an increased resistance training capacity may lead to muscle gains over time.

Weight Gain With Resistance Training

Resistance training places a heavy load on a muscle cell and creates an increase in protein synthesis in the muscle cells and the cells increasing in size by incorporating more protein. Secondly the myofibrils in each cell may multiply, which will increase the size of the muscle fiber. Thirdly the amount of connective tissue surrounding the muscle fiber and around each bundle of muscle may increase and thicken, again increasing the size of the muscle. Fourth, the cell may increase its content of enzymes and energy storage, particularly ATP (muscle energy) and muscle glycogen levels.

The increased muscle glycogen along with the increased muscle protein binds additional water which contributes to an increased bodyweight. Studies have also shown that resistance training exercises may increase bone mineral content, with the possible increase in muscle tension effects on the bone and which may also increase bodyweight slightly.

Resistance training may be effective in increasing muscle size and mass and as such help improve muscular strength and endurance and both are important in weight control programs. Females who perform resistance training normally do not experience the same amount of hypertrophy (muscle size) that males experience with the same amount of resistance training although they do experience gains in muscular strength and endurance.

Types of Resistance Training for Increasing Bodyweight.

There are many methods of resistance training. Isometric training involves a muscle contraction against an immovable object like trying to trying to pull a fence post out of a hole. If you managed to pull the fence post out of the ground then you would be performing isotonic type movement. Isotonic training involves two types of movement.

Firstly the concentric movement means shortening the muscle as you would experience when performing a bicep curl. The second movement is the eccentric phase which means the muscle is lengthening even though the muscle is still contracting, as in the down phase of the bicep curl, the muscle is contracting eccentrically as it slows the decent of the weight even though gravity is trying to pull the arm down to the start position.

Another form is Isokinetic type training which involves resistance machines that regulate the resistance as you are trying to perform the exercise, as happens with Nautilus type machines. Studies have shown that resistance training with free weights is the most effective method of increasing the size and weight of muscles provided that the basic principle of overload is followed.

The Basic Principles of Resistance Training.

The principle of overload is the most important principle in all resistance training programs. The use of weights places a greater stress on the muscle cell. This overload stress stimulates the muscle to grow and become even stronger to overcome the increase resistance imposed by the weights. So to continually overload the muscle you must increase the volume of training that the muscle must do, another way is to increase the number of repetitions and sets that you perform. Although there is no single best combination of sets and repetitions, usually two or three sets with 8-12 RM (repetition maximum) provide an adequate training stimulus for muscle growth. If you know your 1RM (Maximum weight that can be used for 1 repetition with strict form) you should be able to do 8-12 RM if you use 60-80 percent of your 1RM value. As the muscle continues to get stronger during the training program, you must increase the amount of resistance training overload to continue to get the proper stimulus for sustained muscle growth. This is known as principle of progressive resistance exercise (PRE), another basic principle of resistance training. After a learning period the normal recommended program for beginners is three to five sets with 8RM in each set, the first step is to find out the maximum amount of weight that you can lift for eight repetitions. If you can do more than eight repetitions, the weight is too light and you will need to increase weight. As you get stronger during the weeks you will be able to lift the initial weight more easily, when you can perform 12 repetitions, add more weight to force you to go back to the eight repetitions, this is the progressive resistance principle. Over the next several months you will probably need to increase the weight several times as you get stronger.

The principle of specificity is a broad training principle with many implications for resistance training, including specificity for various sports movements, strength gains, endurance gains, and body weight gains. An example would be a swimmer who wants to gain strength and endurance for a specific swimming stroke should find a resistance program that exercises the specific muscles in a way as close as possible to the form used in that particular stroke. If you want to gain muscle mass in a certain part of the body, those muscles must be exercised.

The exercise routine should be based on the principle of exercise sequence. This means that if you have ten exercises in your training routine then they should be arranged in an order so that muscle fatigue does not limit your ability to lift. For example the first exercise in the routine might stress the biceps and second the abdominals, the third the quadriceps etc. After you perform one full set of all the exercises you then do a complete second set, followed by a third set depending on how long you have been lifting. This training approach is best for beginners to training. Another popular method is to do three sets of the same exercise with a small rest in between the exercises and then perform three sets of the second exercise and so on. This type of training is very effective but may be fatiguing for the beginner at the outset. Beginners should start on an all over body routine as stated above to allow an adaptation by the body to weight training before moving onto a split type routine (splitting the body into different muscle groups to be trained on different days)

The Principle of exercise recovery states that resistance training if done correctly achieves the greatest gains and also imposes a severe stress on the muscles, requiring a period of recovery both during the workout and between workouts. For beginners resistance training should generally be performed about three days per week, with a rest day in between sessions. This rest day allows time for the muscles to repair and to synthesise new protein as it continues to grow.

Bulk-Up Method of Resistance Training.

If your goal is to increase a large amount of muscle mass then you may wish to use the bulk-up method of resistance training. This method involves the use of exercises to stress the major muscle groups of the body. About three to five sets of each exercise is performed.

The use of 8-12 repetitions is recommended for beginners and using the principle of progressive resistance exercise you start with a resistance that you can perform eight repetitions and progressively increasing the repetitions to twelve. After you reach the twelve you must increase the weight until you again achieve the lower of the repetition being used, in this case 8.

The bulk-up method should be used for several months to increase the body weight. Once you have achieved the weight that you want to be at, you may then wish to shape the bulk or known as “cutting up.” Again once you have achieved the reduction of bodyfat in the cutting phase that you want, you again hit a bulking up phase, this technique is used to both maintain weight and shape.

Good luck! If you have any more questions, ask on our forum.

Nutrition for Health, Fitness & Sport; Melvin H. Williams
Advanced Sports Nutrition; D Benardot.

Rajesh Gopidi
Posted on: Mon, 01/23/2017 - 14:52

Hi Doug,
Thanks for the great article. Can you please list a set of exercises for a beginner looking to do resistance training in sets are suggested in the article.


Posted on: Wed, 05/09/2012 - 22:22

Good Article, thanks for sharing

Posted on: Tue, 10/05/2010 - 13:34

Hello Doug and congratulations for the article. I am 25 years old, 179ψμ and 80 kg and my training method is to perform 8 reps and if i do them without help from my partner then i increase weight in order to perform at least 6 reps. Is it wise?

M&S Team Badge
Posted on: Thu, 10/07/2010 - 09:39

Hi Kyriakos,

That is a solid approach.