Recently, some research and literature have surfaced about how and why it is so hard to lose weight and keep it off.
The research I’m referring to was done by Rupert Leibel at Columbia University. In a nutshell, he carefully controlled subjects weight-loss or -gain via liquid only diets to then observe what the effect was on metabolically active tissue (read: muscle). What he found is both fascinating and hugely enlightening:
The research shows that the changes that occur after weight loss translate to a huge caloric disadvantage of about 250 to 400 calories… Muscle biopsies taken before, during and after weight loss show that once a person drops weight, their muscle fibers undergo a transformation, making them more like highly efficient “slow twitch” muscle fibers. A result is that after losing weight, your muscles burn 20 to 25 percent fewer calories during everyday activity and moderate aerobic exercise than those of a person who is naturally at the same weight.
In my opinion, unless you are a COMPETITIVE endurance athlete, slow-twitch fibers are simply “the worst.” Not only do they turn your body into a Prius in terms of efficiency (and speed, power, and all the cool by-products of training), BUT they are also quite easy to develop in comparison to fast-twitch fibers. For example, high-school athletes who join the cross-country team to “get in shape” for basketball season are doing themselves a MASSIVE DISSERVICE! All they’re effectively doing is engaging in a form of activity that will not prep them for basketball and WILL prep them to be slower and weaker on the court.
Sorry, I got off on a bit of a tangent, back to interpreting the research: the reduction in caloric burn post-loss is a big key to understanding why continued weight-loss becomes so difficult after a certain period of time. Anyone who has ever tried to lose weight knows there is a plateau that can be very difficult to surmount for further progress.
So far the two key points are 1) weight-loss results in metabolically active tissue reducing caloric burn by 20-25% and effectively creating “looks like, feels like” slow-twitch fibers, and, 2) the body’s newly established efficiency is why weight-loss stagnates.
The good news here is you can beat the plateau by sticking with a strength-training routine (one of moderate to rigorous intensity will pay the best dividends) while continuing a eating plan that lines up with your goals.
To address my tangent on endurance training/slow-twitch fiber development from above: you MUST add in cardiovascular/conditioning work, just make sure it’s going to deliver the most bang-for-your-buck! Prioritize things like sprints, farmer’s walks, Prowler pushes, total body circuits, etc at a frequency of 3-4x/week. Save the steady-state cardio for off-days when you want to recover and also want to burn extra calories (this is 2x/week maximum).