**3. Resistance training as an adjunct weight loss strategy**

It is critical to note that many weight loss programmes incorporating diet-only and/or even aerobic-only exercise results in weight loss as a result of a deleterious reduction in muscle mass [16], sometimes even without a decrease in fat mass [16]. When it comes to weight loss, it is clear that a combination of interventions is more

### *Resistance Training and Weight Management: Rationale and Efficacy DOI: http://dx.doi.org/10.5772/intechopen.101840*

effective than a single intervention strategy [17]. Thus, it is critical for clients and health professionals alike to emphasis body recomposition, rather than weight loss, since it focuses on the process of changing the ratio of fat and lean mass, with a focus on losing fat mass while gaining muscle mass. In this regard, research indicates that resistance training (RT) as an exercise modality is most effective at increasing lean mass [8]. RT, also known as strength training or weight training, is any type of exercise in which a muscle or muscle group has to overcome some sort of external resistance. This can be achieved through a variety of techniques, including incremental weight increases, the use of a variety of exercises and types of equipment to target specific muscles or muscle groups. As such, RT can also incorporate a variety of training techniques, such as callisthenics, Pilates, yoga, free weights, weight machines, resistance bands, isometrics, high-intensity interval training (HITT) and plyometrics.

Problematically, a challenge to body recomposition and RT's unpopularity in weight management is that this loss in fat mass coupled with an increase in fat mass results in a relatively stable weight, that is undesirable by those engaged in "weight loss". In addition, due to this stigma of an increased muscle mass following RT, many individual engaging in a weight management programme fail to engage in RT [18].

RT results in a plethora of physiological changes and adaptions that are well suited to weight loss and body recomposition. In this regard, a unique feature of RT is its ability to maintain or increase muscle mass. It is this increase in muscle mass that not only offsets declines in performance and health, but also increases metabolic rate. In this regard, while aerobic exercise may burn slightly more calories per hour than RT (i.e. running at five miles per hour burns approximately 606 calories per hour for a 73 kg individual versus a general resistance training session for 1 h that burns an average of 448 calories per hour for a 70 kg individual), each kg of muscle burns off around 13 calories per day [19]. As such, even a modest 5 kg increase in muscle mass will result in an additional 65 calories being burnt daily. Further, research has demonstrated that while caloric expenditure of RT is only slightly less than aerobic exercise, excess post-exercise oxygen consumption (EPOC) and post-exercise caloric expenditure are higher following RT (even when matched for oxygen consumption and equal durations) [20] and this may have an additional favourable consequence on weight management programmes.

Physiologists may be interested in the effect of exercise on basal metabolic. rate, fat size and distribution, and dietary-induced thermogenesis, whereas other scientists, such as nutritionists and psychologists may be concerned about the possible effect of exercise on other factors, such as habitual nutrient intake, and effect on body image and self-concept, feelings of well-being and adherence, respectively. In this regard, the addition (but not sole use) of RT to aerobic training can reduce the amount of total calories, carbohydrates, proteins and fats consumed and as such promotes a favourable improvement in self-reported dietary intake [21].
