Although the vast majority of our clients are trying to shed pounds, some may be trying just as hard to gain weight. Many fitness professionals also have difficulty keeping weight on, owing to their demanding physical jobs and busy lives.
This may sound like an enviable position to be in, but gaining weight is not without its own challenges: For example, is it possible to gain muscle over fat? What constitutes a healthy weight gain? And what role does exercise play in attaining this goal?
The purpose of this article is to provide a brief overview of research in this area and to summarize practical strategies for those struggling to gain weight.
Not Any Gain Will Do
Weight gain that occurs primarily from overeating without also regularly exercising will result in increased fat mass. It is estimated that for every 1 pound of body weight gained while sedentary, about two-thirds of the gain is in the form of fat storage (Tremblay et al. 1992). That’s why nutrition experts say the healthiest approach to weight gain is to focus on adding more lean body mass and less fat mass.
Additionally, a balanced food plan is crucial to ensure that the higher caloric intake needed for weight gain is achieved in a nourishing way. The best way to ensure healthy weight gain is to use a multifaceted approach that incorporates exercise and sound nutrition, a strategy outlined in the sections that follow.
Rely on Resistance Training
If a client’s goal is to gain lean body mass, the focus should be on trying to increase muscle mass; in other words, to achieve muscle hypertrophy. Muscle hypertrophy occurs from the synergistic interaction of feeding (i.e., caloric intake) and resistance exercise, which together stimulate the cellular process of protein synthesis (Phillips, Hartman & Wilkinson 2005).
A review of the research on this topic indicates that a wide variety of resistance training programs are effective in stimulating muscle hypertrophy (Carpinelli, Otto & Winett 2004). For example, one set consisting of 3–15 repetitions of each exercise targeting the major muscle groups appears to be just as effective at inducing muscle hypertrophy as multiple-set training regimens (Carpinelli, Otto & Winett 2004).
When designing a strength training program for a client who wants to gain weight, it is best to prescribe a resistance that will enable the client to perform each exercise to fatigue (i.e., completing that last repetition should be difficult) while still maintaining good form (Carpinelli, Otto & Winett 2004). According to the American College of Sports Medicine, progressively overloading the muscle by increasing the load 2%–10% as the muscles adapt will sustain the stimulus for muscle hypertrophy (ACSM 2002).
In terms of frequency, strength training should be performed two or three times per week for a full-body routine, or four to six times a week for a split-body workout, alternating the upper and lower muscle groups. Always allow at least 48 hours’ rest between workouts that target the same muscle groups, to allow for the repair and growth of muscle fibers (Hass, Feigenbaum & Franklin 2001).
Vary Protein Intake
Amino acids are essential for protein synthesis and therefore must be available in sufficient quantities to support muscle hypertrophy. However, the body is extremely good at recycling amino acids, and research suggests that regular resistance training enhances the way the body uses protein (Phillips 2004).
Most Americans get more than enough protein in their daily diets, typically consuming amounts above the Recommended Dietary Allowance established for sedentary individuals; that is, more than 0.8 gram (g) per kilogram (kg) of body weight per day (National Research Council 1989). However, protein requirements for athletes who engage in strength training may be as high as 1.6–1.7 g of protein per kg of body weight per day (Lemon 1998). So these clients may need to increase their protein intake, despite the possible increased efficiency in protein use associated with exercise.
Even these higher protein intakes for athletes are not all that difficult to achieve. This is especially true since the added caloric intake needed to support exercise typically provides added grams of protein. Thus, there is no need to supplement normal dietary protein with expensive protein supplements (Phillips 2004).
To ensure that intake of dietary protein includes all the required essential amino acids, it is best to eat a wide variety of protein-rich foods. This is especially important for individuals who adhere to a strict vegetarian diet. For a look at some food sources, see “Recommended Sources of Protein,” above.
Another consideration should be the saturated-fat content of the protein source. Although research in recent years has identified the importance of healthy fats, such as essential fatty acids, it is important to limit saturated fats, which increase the risk for a variety of diseases. See “Comparing Saturated-Fat Content in Protein Sources” on page 75.
Count on Carbs
Although it is not necessary to amp up protein intake to gain lean mass, carefully timing when other specific nutrients, such as carbohydrates, are ingested can indeed stimulate muscle protein synthesis (Lemon, Berardi & Noreen 2002; Rennie 2005). That’s why experts recommend that all snacks eaten before an exercise session include both protein and carbohydrate. Quick examples include a sliced hard-boiled egg on toast or whole-wheat crackers spread with low-fat cheese.
The time periods immediately before and after strength training appear to be optimal for ingesting carbohydrate and amino acids to enhance muscle protein synthesis (Rennie 2005). Studies have shown that supplementation with essential amino acids (i.e., those not produced within the body) immediately after resistance exercise can significantly increase net muscle protein synthesis (Borsheim et al. 2002).
Increase Caloric Intake
To achieve weight gain, caloric intake must be adequate, or the body will burn protein calories for fuel instead of releasing them to build muscle (Lemon 1998). That’s why it is essential that total energy needs are being met when attempting to increase muscle mass (Lemon 1998).
Here are the three main things to consider when calculating the correct caloric intake for clients who want to gain weight:
Calories for Weight Maintenance. These are the calories needed to maintain one’s current weight. To calculate daily maintenance calories, use the formula of 16 kilocalories (kcal) per pound (35 kcal per kg) of body weight for females or 17 kcal per pound (37.5 kcal per kg) of body weight for males (Williams 1999). But keep in mind that this formula estimates caloric needs for adults engaging in light daily activity, and the number of calories can vary greatly based on individual differences. Caloric intake will need to be increased as clients gain weight, in order to maintain the added muscle mass.
Calories for Exercise. The caloric cost of strength training is difficult to determine and can vary widely depending on each training session’s load and volume. Some experts recommend using an energy cost of 200 kcal per strength training workout for the average-sized male and 150 kcal per workout for the average-sized female (Williams 1999). However, for larger or more athletic clients, the caloric cost of resistance training could be significantly higher.
Calories for Muscle Synthesis. Research on the exact number of calories needed to fuel muscle protein synthesis is scarce. However, it has been suggested that an increase of 400 kcal per day will support muscle tissue synthesis of approximately 1 pound per week.
Clients should aim for 1/2 to 1 pound of weight gain per week (Williams 1999). Take baseline body composition measurements (i.e., skinfolds, hydrostatic weighing, bioelectrical impedance, etc.), and reassess clients every month or two to ensure that their percent body fat remains stable. If significant rises in body fat occur, decrease caloric content by 100 to 200 kcal per day, and then monitor subsequent changes.
The maximal rate of lean body mass that can be sustained over a 1-year time period is approximately 0.4 pound per week (Gatorade Sports Science Institute 1994), although larger weekly increases may be seen during the initial phases of training.
Remember that slow gain is best: Rushing the process just increases the chances that most of the weight gained will be in the form of fat mass instead of the desired lean body mass.
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*Adding dry milk powder is an excellent way to increase the protein content of fruit smoothies, shakes or baked goods.
Source: NutriBase 5 software program by Cybersoft Inc.
It is often difficult for fitness professionals to gain or maintain body weight when training clients all day long. To avoid using all your hard-earned muscle mass for fuel, you must take in adequate calories. Try these tricks at home!
1. Right before and after working out, consume snacks that mix protein and carbs. This will help maintain muscle mass and replenish glycogen stores.
2. Replace some of your water intake with sports drinks or juices to boost caloric intake.
3. Eat energy-dense snacks every 3–4 hours. Examples are fruit smoothies with added dried milk powder; energy bars; crackers or tortillas with nut butters and/or cheese; nuts and seeds; dried fruit; and trail mixes.
4. Add healthy fats to the diet to increase daily calorie intake, but focus on monounsaturated fat sources, such as olive oil.
Food Item Protein Saturated Fat Food Item Protein Saturated Fat
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American College of Sports Medicine (ACSM). 2002. Position Stand: Progression models in resistance training for healthy adults. Medicine & Science in Sports & Exercise, 34, 364–80.
Borsheim, E., et al. 2002. Essential amino acids and muscle protein recovery from resistance exercise. American Journal of Physiology, Endocrinology and Metabolism, 283, E648–57.
Carpinelli, R.N., Otto, R.M., & Winett, R.A. 2004. A critical analysis of the ACSM Position Stand on resistance training: Insufficient evidence to support recommended training protocols. Journal of Exercise Physiology online, 7 (3), 1–60.
Gatorade Sports Science Institute. 1994. Methods of weight gain in athletes. Sports Science Exchange Roundtable #21, 5 (1). www.gssiweb.com/reflib/refs/60/d0000 00020000004c.cfm?pid=38.
Hass, C.J., Feigenbaum, M.S., & Franklin B.A. 2001. Prescription of resistance training for healthy populations. Sports Medicine, 31 (14), 953–64.
Lemon, P.W. 1998. Effects of exercise on dietary protein requirements. International Journal of Sports Nutrition, 8 (4), 426–47.
Lemon, P.W., Berardi, J.M., & Noreen, E.E. 2002. The role of protein and amino acid supplements in the athlete’s diet: Does type or timing of ingestion matter? Current Sports Medicine Reports, 1 (4), 214–21.
National Research Council. 1989. Recommended Dietary Allowances (10th ed.). Washington, DC: National Academy Press.
Phillips, S.M. 2004. Protein requirements and supplementation in strength sports. Nutrition, 20 (7), 689–95.
Phillips, S.M., Hartman, J.W., & Wilkinson, S.B. 2005. Dietary protein to support anabolism with resistance exercise in young men. Journal of the American College of Nutrition, 24 (2), 134S–39S.
Rennie, M.J. 2005. Body maintenance and repair: How food and exercise keep the musculoskeletal system in good shape. Experimental Physiology, 90 (4), 427–36.
Tremblay, A., et al. 1992. Overfeeding and energy expenditure in humans. American Journal of Clinical Nutrition, 56 (5), 857–62.
Williams, M.H. 1999. Weight gaining through proper nutrition and health. Nutrition for Health, Fitness & Sport (5th ed.). Dubuque, IA: WCB/McGraw-Hill.