The conventional advice given to those who are trying to obtain a goal of weight-loss is to “eat less and move more.” This operates under the calories in, calories out model whereby you need to exercise off more calories than you have coming in. Sounds great in theory, but I am here to tell you that a calorie is not a calorie and exercise doesn’t really burn that many to begin with.
During a simple calorie restricted diet the weight lost is usually comprised of 2/3 fat and 1/3 muscle. So, if you lose 15 pounds, approximately 10 pounds would come from fat and the other 5 pounds from muscle. The loss of muscle is unfortunate and in a perfect world (e.g., prioritizing adequate amounts of protein in the diet) would not be as significant, however if you are following the “eat less and move more” mantra this is pretty much to be expected.
Take a look at this example: a 200 pound woman with 30% body fat (200 x 30% = 60 pounds of fat mass), after losing 15 pounds would weigh 185 pound with 50 pounds of fat mass. She lost 10 pounds of fat and her total body fat was reduced from 30% to 27%.
While a total loss of 15 pounds is worth bragging about, as per the above example, the loss in muscle mass will cause a reduced metabolic rate, slowing down continued weight loss. In other words, because she burned off 5 pounds of muscle it will be harder to continue losing weight as easily as it would be if she hadn’t lost 5 pounds of muscle. Why? Muscle is an expensive tissue to maintain, it consumes nearly 40% of your body’s resting metabolism. To combat the negative effects of reduced muscle mass, while seeking a goal of body recomposition, it is important to increase total protein intake as to not hinder future progress,
Dietary protein requirements are largely affected by the amount of muscle mass you carry around as well as your total calorie intake. There is an inverse relationship between calories and protein, whereby increasing calorie intake reduces dietary protein requirements, while reducing calorie intake increases dietary protein intake. Applying this to the above situation, our 200 pound woman would make better long-term progress from an increased total protein intake of say 150-180 grams: 180 grams of protein x 4kcal/g = 720 kilocalories from protein; 720 calories is 36% on a 2000 kilocalorie diet and is 48% on a 1500 kilocalorie diet. Thus, the absolute and relative amounts of protein in the diet are increased. By doing this, muscle mass is much more likely to be retained, improving long-term weight loss and body recomposition goals. This is clearly supported by clinical trials; high protein diets consistently result in more successful long-term diets…
Exercise is definitely beneficial for optimal health and longevity as it increases overall fitness, improves cardiovascular health, promotes a positive well-being and if done properly can increase muscle mass which can pave the way for a long life full of vitality. However, one thing exercise does not do is cause weight-loss. When someone starts an exercise regimen without a specific dietary intervention, long-term weight loss fails to occur in the majority of people because the calorie deficit produced from exercising is offset by the increased hunger and subsequent food intake. In other words, energy intake will rise to meet the level of energy expenditure. Another way “eat less and move more” falls short of optimal advice.
This is not to say that exercise is worthless when it comes to weight-loss because exercise has the ability to do one thing that dietary intervention cannot: it builds muscle. Learning from the above mentioned example, it is our ability to maintain muscle that creates a beneficial atmosphere around weight-loss because muscle is metabolically active — the more we have, the greater amount of energy we must expend to keep it, even at rest.
For conventional purposes, exercise can be broken down into two categories; aerobic and anaerobic. Aerobic training revolves around extended periods of heavy breathing which makes the heart work and improves cardiovascular fitness, generally at the expense of precious muscle. Examples are running and cycling. Anaerobic training is performed at a much higher intensity than aerobic exercise, albeit much shorter bouts with plenty of rest in between which promotes muscle growth and increased strength. Examples are sprinting and weight lifting/strength training.
While both forms of exercise will increase energy expenditure, the amount of calories expended when not exercising is much greater than those spent when exercising. Time spent not exercising is roughly 45 times greater than time spent exercising (60 minutes at the gym vs. 23 hours not at the gym). Office work, sitting in traffic, grocery shopping, cooking, watching television, and sleeping are all lower intensity activities than any exercise; having a substantial amount of your body composition comprised of muscle will allow you to utilize your calories for the health of that expensive tissue and not have it stored as fat. Therefore, it is important to prioritize your exercise regimen accordingly.
Anaerobic training, specifically strength training increases skeletal muscle mass. This has a positive effect on our metabolic rate allowing us to use energy more efficiently (e.g., burn fat), in addition to improving overall strength, coordination and quality of life. Having stronger muscles makes all activities easier, and thus of lower intensity. And lower intensity favors fat burning as a primary fuel source. In other words, to optimize the effect of exercise on fat burning, get in the weight room.
A better way to think about getting in shape would be to “Eat and Train.” This seems to be a much more productive piece of advice as I have hopefully illustrated above. The idea of “eat less and move more” is aesthetic whereas the other is functional. The former may not have a clear goal, but the latter always does.