CompensationIn 2009, Dr. Timothy Church from Louisiana State University published a research study that looked at the effects of different amounts of exercise on weight loss in postmenopausal women(1). The women were broken up in to 4 groups. The control group performed no exercise and were told to maintain their regular activity while the exercise groups worked out for 72, 134, and 196 min/wk. At the end of the six month study, there was no significant difference between any of the groups in terms of weight loss. In other words, no amount of exercise helped them to lose any more weight than if they had just maintained their regular physical activity. In addition, there was no significant difference in fat loss between the groups. How does this appear to happen? The answer, is compensation.
When people change one lifestyle factor this change tends to cause a ripple effect in other factors. One of the more obvious changes is that when people begin to burn more calories, they also tend to eat more calories. This is why it's so difficult for people to lose weight come January 1st, they decide to substantially increase their energy expenditure while at the same time cutting their caloric intake. This leads to a situation where they are unable to control their appetite because their brain senses increased stress and decreased resources to deal with stress. The natural response of a brain under stress is to increase caloric intake, particularly from carbohydrates as one of the primary roles of the stress hormones, particularly cortisol, is to increase blood glucose levels. It does this by causing the liver to make more glucose and by increasing your appetite for glucose generating substrate, aka carbohydrates. This is why cortisol is called a glucocorticoid, it's secreted by the adrenal cortex to help mobilize glucose. In the above study, there was no difference in self-reported food intake between groups, but this type of reporting of data has been shown to be inaccurate in the past. Increased food intake due to exercise has been identified as an issue in other studies(2, 3) and is a typical issue for most people when they begin an exercise program. This type of compensation can be minimized by introducing exercise stress slowly and not implementing severe lifestyle changes in a sudden, poorly thought out manner.
Compensation from exercise also comes in the form of reduced physical activity throughout the rest of the day. Anybody who has jumped head first in to a program on January 1st can tell you that they will typically be sore the next day. When moving around hurts, it's not too big of a stretch to think that people will do it less. This is a way that we subconsciously compensate for exercise. If the intensity and duration of a workout is going to negatively impact your ability to move the next day, it's definitely not going to help you lose weight.
Many people use large amounts of soreness as an indicator of a good workout, it's not. Pain is one of the ways your body tells you to stop doing something. If you put your hand on a hot stove burner it is the pain that tells you to stop doing it. In the same way, overdoing it in the gym will lead to excessive amounts of soreness the next day and this is not a desired state. It's fine to feel a little tight, but that should be remedied fairly easily with a mild bit of stretching and/or warming up. The same goes for energy levels. After a good workout, you should feel energized and alert, if you feel dead and shot you overdid it.
Using exercise to lose weightWhen working with clients who are just trying to lose weight, the role of exercise in their wellness program is to keep them moving well, pain-free, and insulin sensitive. The first step in this process is to help them move properly. The best way to do this is to utilize the joint by joint approach, which also helps them move pain free. The joint by joint approach identifies which joints are best suited to mobility or stability, and that gives you direction in developing those qualities in the specific joints. Below is a diagram of the qualities each joint is best suited:
Joint by joint mobility/stability requirement
Taken from http://agogeblog.files.wordpress.com/2011/11/joint-by-joint-skeleton.jpg
With every one of our clients, we begin the program with a Functional Movement Screen(FMS) that will identify areas where the quality of movement is poor because one or more joints have dysfunction. When this happens, there may or may not be pain in a separate joint because it is compensating for the other(s). For example, many people with knee pain actually have ankles that are immobile. In order for the kinetic chain to move properly, joints should alternate between mobility and stability. Looking at the diagram, the ankle should be mobile. When it's not, the knee must become mobile to allow movement which can cause pain because the knee is supposed to be stable. Many people will work on strengthening their knee in this situation, but since the problem is at the ankle you need to fix the ankle first. I can't tell you how many times I've had someone come in who has had knee pain from running their whole life that fixes the problem almost immediately by adding ankle mobility work in prior to running.
The FMS is a very easy, yet powerful tool. I remember one 18 year old client who thought she would never get rid of her back pain have it eliminated in 2 weeks just by performing a proper foam rolling/stretching/activation program that utilizes the joint by joint approach. She initially thought it was from an injury lifting up a stage, but lifting the stage merely brought her movement dysfunction to her attention. She had been to chiropractors and physical therapists who couldn't help her, and all she had to do was pay attention to the joint by joint approach and perform a 20-30 minute warm up 2-3 times per week. Be on the lookout as in the near future, I will be posting a video of the dynamic warm-up I do with all athletes and clients. This is the general warm-up we start with, if the FMS identifies an area of need we will add something on top of this to fix the issue locally and then work on restoring the movement pattern(s).
Insulin sensitivityIn terms of improving general health and helping you lose weight, exercise is best used to maintain insulin sensitivity. We have gone over this here and here, so we won't rehash the science on this topic. Intense physical activity a couple of times a week improves your insulin sensitivity and cleans out your glycogen stores, allowing you to consume more carbohydrate before altering insulin sensitivity. This is particularly important if you are obese, diabetic, or prone to either condition as these people tend to carry more of the Type II muscle fiber types(IIa and IIx). To improve insulin sensitivity it is important to activate the Type II muscle fiber types on a regular basis by generating high forces. Since Force=Mass x Acceleration, you can either move heavy objects or perform fast movements.
I personally choose to lift heavy weights 2 times a week for upper body and hit my legs every 10 days, but you could easily play a sport, sprint, or perform a plyometric program. My personal program is pretty simple, for upper body I push in a plane of motion and pull in a plane of motion 2 times a week. One week I'll do 3 sets of 4 reps for each and the next week I'll do 3 sets of 8 reps for each. One day I will push and pull vertically and the other day I'll push and pull horizontally. I also do some core exercises in between sets to give myself a rest and prevent my posture from getting bad. Every 10 days I'll hit my legs pretty hard with plyos, strength training, or sprints. I keep my leg volume pretty low because I'm always doing something active on the weekends. That's it, for someone with my goals(Maintain strength and insulin sensitivity while being healthy) that is pretty much all you need to do. If I enter a stressful week, am not sleeping well, or haven't been getting the proper nutrition I'll dial it back. Someone with less training experience or whose goals include physique enhancement may want more volume, but for the vast majority of people simpler is better.