The Fundamentals of Fat Loss, Part 1: A Comparison of Training Intensities

By John Ellis, CPT

Of any ambition considered universal to the commercial gym member, obtaining an ideal body reigns supreme. Less egoistic desires, i.e. increased health, longevity, mobility, and posture, are less common; even more rare are those whose conception of fitness deals primarily with physical capability and performance. Regardless, the fitness club majority’s most unanimously declared desire is a better looking body, and for most of society this means the incessant battle of the bulge: losing excess body fat.

Commercial fitness organizations have often generalized the matter of fat loss. One-stop-shop calorie-quantification, cliched catchphrases that intimate thermodynamics laws, and gimmicky equipment abound in the fitness industry. As a consequence of this oversimplification of things, the average gym-goer’s attempt at fat loss, at best, is usually intermittent attempts at the most popularized of fitness formats: steady-state aerobic trotting. By this I mean anything done at a constant moderate tempo, on a treadmill, bike, elliptical, etc. Such a default "fitness" fits comfortably into the framework of the modern commercial gym design and requires little understanding on behalf of the participant.

To be fair, to train in a steady-state aerobic manner in such a way as to constitute some measure of conditioning is a necessary part of some athletic programs: Some sport-specific goals require it. Indeed, it will inevitably facilitate some degree of body fat loss. Steady state aerobic work also lays claim to its second most ubiquitously espoused benefit: improving "heart health", cardiovascular function.

In light of the fact that so many use it exclusively as the mainstay of their fitness lives, it is unfortunate that A) it is proven in current literature that steady-state moderate intensity aerobics are a relatively inefficient method toward fat loss, and B) several other corollaries of aerobic conditioning, when it is done as an exclusive training modality, are less than highly vaunted, to say the least: decreases in strength, speed, power, and muscle mass. The former drawbacks may be irrelevant to the weekend treadmill warrior, but the consequence of the latter should be of especial concern to anyone who desires fat loss, not just in the short term but the long term as well. If loss of muscle mass does occur, inevitably a propensity toward higher basal metabolism(rate of burning calories at rest) will stall or drop all together. Were that not enough, training with an exclusively aerobic emphasis will tend to influence a decrease in anaerobic capacity, your body’s metabolic capability in bouts of short-duration, high-intensity activities. On the broad spectrum of "fitness", an aerobic-dominant mentality seems not only narrow in scope, but to some extent, detrimental, or at the very least, counter-productive.

In the gym-goer vernacular, to get more "ripped", AND keep your entire spectrum of health benefits, means that you need to understand the facts and put into practice something that is inevitably not your typical jog-for-forty-five-minutes routine. Regardless of the fitness modality that you prefer, fat loss is more efficient when utilizing a high-intensity interval format. An interval, simply put, is a format that utilizes a relatively brief period of higher intensity movement followed by a brief period of rest or slower intensity movement, repeated. Currently, one of the most popular of these interval formats among athletes, qualified fitness professionals, and fitness enthusiasts alike, is the Tabata interval. Dr. Izumi Tabata and colleagues, based at the National Institute of Fitness and Sports in Tokyo, Japan, created an interval format infamous for its paired intensity and economy. The Tabata interval utilizes just 4 minutes of high intensity work per each bout of training, an obvious contrast to the steady-state paradigm the normal durations of which are a time-sucking 30-60 minutes plus.

The inception of the Tabata interval was particularly ground breaking in exercise science research, proving that training of this kind not only improved general aerobic capacity (VO2max), but anaerobic capacity even more so. Its relevance to fat loss is that weight loss exercise strategies, normally based on maximal energy expenditure, are better utilized when employing severe work formats. As heavy exercise intensities prove to be the most excessive and costly for the body, research shows that relatively shorter durations of higher intensities lead to better lipid (fat) utilization in the body’s post-exercise period of physiological recuperation; greater energy expulsion and lipid deficit means more calories from fat are burned

I’ll conclude with the following: In a Canadian study (Metabolism, 1994, Volume 43, p814-818) comparing moderate-intensity to high-intensity exercise, Canadian Scientists divided 27 inactive but healthy, adults, of both genders, into two groups. One group did a 20-week endurance program of steady state cycling for 30-45 minutes, with an intensity starting at 60% of heart rate reserve progressing to 85%. The other group did a shorter, 15 week program that consisted of much higher intensity interval training. The second group progressed from a short duration of approximate 70% of heart rate reserve into a series of 10 to 15 short duration bursts of 120-130 bpm. The initial intensity of the short intervals was fixed at 60% of maximal work output, the long intervals lasted 90 seconds, at 70% of the individual’s maximal work output. Intensity for both intervals increased 5% every three weeks.

In the end, the energy cost of the initial endurance group was twice that of the higher intensity group. However, skinfold measurements of each group revealed that the loss of subcutaneous fat in the second high-intensities group was astounding greater than that of the endurance group. In comparison of energy costs between the two groups, the subcutaneous fat-loss in the high intensities grouping constituted X 9 greater than that of the endurance group.

All this talk on higher intensities being said, one caveat is that if you are obese, have severe health issues, and/or are not use to intense exercise, then it is absolutely recommended that you seek out a qualified fitness professional to help you determine to what extent you can enter into such a program, and what specific program that might be.

Stay tuned for more articles regarding fat loss fundamentals. I will cover the need to specify training modalities focused on weight lifting ("Why you need to lift heavy objects (safely)" and the nutritional components of achieving fat loss not only as an end but in a safe, efficient manner that supports your long-term health.