Is it possible to lose fat by training muscles in certain parts of our bodies?
Posted Aug 01, 2014
At a recent conference on Women and Sport and Physical Activity, I presented the results from a study I completed with one of my graduate students, where we asked fitness instructors about their understandings of the importance of health and body shape in their practice. In our study, the instructors, while wanting to promote health, believed that their participants are there primarily to lose weight. As one instructor put it: “100% of time” it is about weight. Another believed her participants, who are mostly women, might not always be ”verbal about it,” but weight loss was “the ultimate goal” for exercise.
After my talk, an audience member who identified herself as a fitness enthusiast claimed that women do not come to fitness classes to lose weight, but to lose fat. In her class, the latest trend was to focus on building muscle. Then she asked what my opinion was about muscle-building and fat loss.
Her question points to an important distinction between "body fat" and "body weight." Although they are not the same thing, there are several biological facts supporting a connection between building muscles and fat metabolism.
Biological Fact 1: Muscle tissue is an active, living tissue whereas fat is considered a "storage" tissue. This means that muscles will need more energy than fat to function during the day. This further means that if have a lot of muscle tissue, we need energy to sustain them even at rest. Therefore, increasing muscle tissue increases the resting metabolic rate (energy we consume at rest). This energy can come from fat tissue.
Biological Fact 2: Muscle tissue is heavier than fat tissue. Thus, building more muscle tissue does not necessarily result in weight loss.
Biological Fact 3: Building muscle tissue can improve body composition, one of the components of physical fitness—the other components are cardio-vascular fitness, muscle strength and endurance, and flexibility. Body composition refers to the ratio of "fat components" to "fat-free components" (bone mineral, muscle protein, water and other chemicals) in our bodies. This is usually presented through a percentage of fat comparison to fat free tissue. For example, fat percentage below 20 percent is considered low for women, 28 percent is considered normal, but 35 percent is considered overweight/obese. Body composition can be changed by increasing or decreasing the fat-free component or by increasing or decreasing the fat component. Consequently, building more muscle tissue will increase the fat free component regardless of whether the amount of fat in the body changes. Building more muscle mass that is heavier that fat tissue can, however, increase one’s Body Mass Index (the height to weight ratio), because one’s height stays the same, but one’s weight increases. (See my earlier blog “What Does BMI Tell Us” for a more detailed discussion.)
Biological Fact 4: "Spot reduction" is not possible. It is a common assumption that exercising certain areas of the body will reduce the surrounding fat storage in that area. For example, doing a lot of abdominal crunches will make our stomachs flatter. Or doing a lot of triceps extensions will make the underarms thinner. Or doing a lot of leg lifts to the side will make the pelvis smaller.
Body fat is used or metabolized in a generic manner and thus, it is not possible to reduce the fat storage on a particularly spot by exercising in and around that spot. It is, however, possible to strengthen particular muscles by training them specifically. For example, crunches will train (primarily) rectus abdominis, the most superficial of the three layers of abdominals. Triceps extensions will strengthen triceps humerus and leg abductions will strengthen gluteus medius and minimus.
The instructors in our study were aware of these facts and uniformly condemned "spot reduction" as a fallacy. One instructor acclaimed: "There’s no such thing as spot reduction … don’t try to make yourself do 200 crunches a day to get rid of it ... all that’s going to do is make the fat sit a bit nicer, but it’s not going to remove that fat."
Whether the fat "sits a bit nicer" is questionable, but the muscles around it will grow in size when targeted with resistance exercises. Instead of spot reduction, the instructors recommended living a balanced lifestyle including cardio-vascular exercise and following a healthy diet for weight loss.
Biological Fact 5: Muscles contract to move our bones to then enable us to move in space. If concerned with the primary function of the muscles (movement ability by increased muscle strength and endurance), any exerciser should focus on strengthening the weaker body parts such as the upper and lower back or the front of the shin or stretch the tight body parts such as hip flexors, necks, or gluteus muscles. If the primary concern is to move better, why then do we care about fat metabolism?
The same biological facts were used already in the 1990s when I was an aerobics instructor to entice women to engage in resistance training. As resistance training improves muscle strength and endurance (another component of physical fitness), it is curious, then, that we felt the need to persuade women to train their muscles for fat loss, not for improved strength. In addition to plain biological facts there seemed to be a number of "social facts" that we needed to overcome when "muscle building" was concerned.
Social Fact 1: Women tend to prefer cardio-vascular training to resistance training. Some of the instructors in the study found that their clients preferred cardio-vascular exercise that resulted in weight loss rather than resistance training designed primarily to build strength. One instructor explained: “I think women focus on problem areas, so they think they have to do cardio to get rid of that and they forget about muscular strength.” If muscle building can be justified to serve fat loss, it will not be forgotten so easily.
Social Fact 2: Women prefer to train specific spots in their bodies. Even when using the "fat loss logic," the participants want to train select parts of their bodies: the under arms, stomachs, hips, and thighs. The instructors in our study confirmed this trend. They noted that "the stomach" was a definite problem area for women, followed by legs and thighs, bottoms, and flabby arms. As one instructor summarized: “Stomachs, stomachs, stomachs... and then their bottoms. Sometimes you get complaints about legs, flabby arms, but it’s for sure stomachs number 1, stomachs and butt.” These are the "problem spots" of the feminine body that need to be reduced in favor of others. The belief in "spot reduction" remains strong although not grounded in biological facts.
Social Fact 3: These problem spots are the parts of the female body where fat is stored. They, thus, define us as biological females. They are, thus, not biologically a problem, but rather a social problem. Why?
Building muscle mass will increase metabolism and some of this energy might come from our fat storages. Muscles, however, are not created as a means for fat loss. However, the "fat loss logic" intertwines fat metabolism with training for increased strength. These are used together to shape thinner and more toned bodies. Although the "problem spots" are natural features of the female body, they become a problem when the ideal feminine body is defined as firm, toned, (although not too visibly muscular) and low overall body fat. Some researchers argue that this shape resembles more of an adolescent male body than a mature woman’s body (Bartky, 1998; Bordo, 2003).
Social Fact 4: The ideal feminine body has a very narrow social definition, although biologically women come in different shapes. Because few adult women "naturally" possess the socially defined body ideal, most women are destined to have some, often diverse body problems. As one instructor explained:
"Everybody’s body type is different. ‘It’s my muffin top, it’s my flabby thighs, it’s my cellulite, it’s my grandma arms, it’s my double chin.’ I mean, it’s because we all are built differently. So everybody has an issue with something."
Although the female body’s physiological function is perfect (e.g., we store fat in the correct places), it is less than perfect in the social world of ideal femininity. Women then, have to negotiate these two worlds by accepting that their biological bodies do not match the requirements of the "social body." One way to deal with this is to accept one’s body shape and then engage in continual body work to improve its worst aspects. For example, one of the instructors urged her participants to accept their less than perfect body shapes:
"I found this triangle thing that’s got pumpkin people and pear people. I’ll [ask the participants]: “What type are you?” and they [say] “Maybe that’s me?” Well guess what? You’re not going to change that. That’s OK. We’re all there."
Based on this logic, changing from "a pumpkin" or "a pear" into toned and slender is purely impossible. "A pumpkin" or "a pear" shape is, of course, not ideal and thus, women with these bodies are destined to appear unattractive, a social fact that they have to accept.
It is, indeed, difficult to change the shape of one’s biological body, its metabolism, or the muscle physiology. Is it equally difficult to change the social facts? If we can’t change our body shapes, why not the change the current notion of the ideal feminine body? After all women come in diverse shapes and sizes. This would allow us to train our muscles for what they are meant for: improved movement ability. We could forget "the fat logic," the problem spots, and the impossible spot reduction to enjoy what our bodies do the best: move.
Bartky, S. (1998). Foucault, femininity, and the modernization of patriarchal power. In I. Diamond & L. Quinby (Eds.), Feminism and Foucault: Reflections on resistance (pp. 61-86). Boston, MA: Northeastern University Press.
Bordo, S. (2003). Unbearable Weight. Feminism, western culture, and the body. Berkley: University of California Press.