By Dan Martin
First of all, prepare for a mouthful of research data. Without it, anything I say won’t matter. Anecdotes and instagram posts about fat loss carry about as much weight as a balloon (no water balloons allowed). Before getting too deep into this, let me be clear – exercise is very important to longevity and health for a large range of factors. Six pack abs won’t make you happy, but working out can certainly release hormones that make you happier, and the side effects of having a good body image can work wonders.
So yes, there are best practices for exercise to maximize fat burning when done with consistency.
Lets dig in…
In a study published in and reported by The New York Times, overweight men and women who exercised six days a week lost weight; those who worked out twice a week did not.
Current recommendations state that exercise programs should be over 225 minutes a week to induce clinically significant weight loss; however, in the study the average weekly exercise time for all participants was just over 249 min, producing nonsignificant decreases in percent body fat loss. The 6 day a week group exercised more than 320 minutes a week to experience significant decreases in body fat. Therefore, the results of the present study suggest current recommendations for exercise to promote weight loss may be inadequate and should be closer to 300 min·wk to overcome the approximately 1000 calorie compensation compensatory response that accompanies exercise.
A 2010 study stated that the effect of regular aerobic exercise on body fat is negligible; however, other forms of exercise may have a greater impact on body composition. For example, emerging research examining high-intensity intermittent exercise (HIIE) indicates that it may be more effective at reducing subcutaneous and abdominal body fat than other types of exercise. (1)
Exercisers can burn slightly more body fat with interval training than moderate-intensity continuous training, according to a recent systematic review and meta-analysis in the British Journal of Sports Medicine. Although the differences in fat loss weren’t huge, the interval workouts were shorter, which could make it easier for people to adhere to them.
One very underappreciated fact about exercise is that even when you work out, those extra calories burned only account for a tiny part of your total energy expenditure.
“In reality,” said Alexxai Kravitz, a neuroscientist and obesity researcher at the National Institutes of Health, “it’s only around 10 to 30 percent [of total energy expenditure] depending on the person (and excluding professional athletes that workout as a job).”
A study, published in the International Journal of Sport Nutrition & Exercise Medicine, involved 73 healthy adults aged 19-63 (41 men; 32 women). It tested the lifestyle and biological factors for optimal fat burning by asking participants to take part in a cycling fitness test and measuring key indicators.
Their results found that females and those who were physically fitter, right across the age ranges, burnt fat more efficiently when exercising. Basically, if you’re already fit, you have optimized yourself into a fat burning machine. It should also be noted that in order to achieve fitness, one has to abide by a relatively healthy diet.
In another study, to determine the effects of a 15-week high-intensity intermittent exercise (HIIE) program on subcutaneous and trunk fat and insulin resistance of young women, subjects were randomly assigned to one of the three groups: HIIE (n=15), steady-state exercise (SSE; n=15) or control (CONT; n=15). HIIE and SSE groups underwent a 15-week exercise intervention. The subjects were forty-five women with a mean BMI of 23 and age of 20.
Both exercise groups demonstrated a significant improvement in cardiovascular fitness. However, only the HIIE group had a significant reduction in total body mass, fat mass, trunk fat and fasting plasma insulin levels. There was significant fat loss in legs compared to arms in the HIIE group only. Lean compared to overweight women lost less fat after HIIE.
Yet another study results in mice and humans show that in response to mechanical loading, muscle cells release particles called extracellular vesicles that give fat cells instructions to enter fat-burning mode.
John McCarthy, Ph.D., study author and associate professor in the UK Department of Physiology says,
“To our knowledge, this is the first demonstration of how weight training initiates metabolic adaptations in fat tissue, which is crucial for determining whole-body metabolic outcomes. The ability of resistance exercise-induced extracellular vesicles to improve fat metabolism has significant clinical implications.”
It should be noted that there is very strong evidence that self reporting of food intake fails and almost everyone undercounts.
Research examining the effects of HIIE has produced preliminary evidence to suggest that HIIE can result in modest reductions in subcutaneous and abdominal body fat in young normal weight and slightly overweight males and females. Studies using overweight male and female type 2 diabetic individuals have shown greater reductions in subcutaneous and abdominal fat. Basically, if you’re overweight or obese, you’ll lose fat quicker, a fact I have seen in practice time and time again.
The mechanisms underlying the fat reduction induced by HIIE, however, are undetermined but may include HIIE-induced fat oxidation during and after exercise and suppressed appetite. Regular HIIE has been shown to significantly increase both aerobic and anaerobic fitness and HIIE also significantly lowers insulin resistance and results in increases in skeletal muscle capacity for fatty acid oxidation and glycolytic enzyme content.
So, now that we have the science – what does this all mean? Well, short bursts of intense exercise repeated with short rest breaks can really work wonders. Studies have been done with as little as 3 minutes of alternating 6 seconds of maximum intensity followed by 9 seconds of recovery. Mind you, these tests are done on high level athletes and most humans cannot perform at this level.
For most people, doing things like 20 seconds of intense cardio followed by 40 seconds of rest for 10 sets can do a lot. When applied with a superset or two of strength work (a formula I use is two alternating exercises done as an every minute on the minute set (EMOM)) you can get a fantastic fat burning workout in 10 minutes.
NOW – while I have stated that low level aerobic work does not do a lot for fat burning, it can do a lot for many other parts of your life. Walking does help maintain muscular and skeletal mass, very important as we age. It can also do good things for our emotional and mental well being. Just getting out and moving is important and should be prioritized.
Finally, and most importantly, no exercise routine is nearly as important as your routine with food. Without a structured plan for eating, you’ll be rowing in circles with one oar. The real magic bullet for fat loss is not exercise, it’s nutrition, sleep and exercise put together. You cannot have one without the other and hope for results – especially as we age.
All that said, it is important to work out and do something you enjoy. If you want some help with your specific plan, reach out. I pay a coach to write my workouts based on my current goals. Even as a professional trainer, I love the ability to login to an app and be told what to do to reach my goals. It also holds me accountable because I know once a month my coach will look at my workouts and progress. He won’t get mad if I don’t do something, but he will give me a, “ what the heck – i thought you cared about this stuff!” …and I do, and then I do better, not perfect.
