The spot reduction myth will never die. The idea that through specific exercises or fitness gadgets you can target fat loss on your belly, love handles or thighs is as old as fitness. Here is why it can’t work.
Tons of places in your body demand energy: your hair wants to grow, your heart wants to beat, your leg muscles try to get you up the stairs etc.
As it would be much too complicated for you body to monitor the energy needs of each of its millions of cells separately, it came up with a simple, yet elegant system: Energy is provided in a common pool, and every cell can access this pool when it needs.
This pool is your blood stream, and the two major forms of energy used by your body, carbohydrates and fat, float through it in the form glucose and fatty acids. When- and wherever a cell needs either, it waits for one to come along, signals it to stop and consumes it.
For the fatty acids all your body then has to do is keep a check how many of them are in the blood stream. When the level falls, it knows more energy is needed and orders the fat storages, your fat cells, to convert the stored fat into fatty acids and set them free.
Without this order the fat couldn’t be used, because in stored form its like raw oil – as gasoline it runs your car, but try doing that with raw oil.
Fat And Muscle Cells Don’t Communicate
This system raises efficiency, as the muscle cells of the muscle you work on when you exercise only have to worry about signaling a floating along fatty acid to stop. They don’t care where it was released.
Your body, on the other hand, doesn’t need to know where exactly fuel is needed and only has to make sure that a constant amount of it is available in the common pool.
Because of the way this system works, your muscles don’t even talk to the fat cells.
You could also imagine it the other way around. If every cell of your body would directly talk to the fat cells, some cells might never get fat as fuel, because they have next to no fat cells in the neighborhood. And total chaos would ensue if every cell held its own negotiations with the fat cells.
In Scientific Research
So much for boring theory, here are two practical scientific experiments that looked into this: Already in 1984 a group of scientists had volunteers do sit-ups for 27 days. During those 27 days these people did more than 5000 of them. At the beginning of the experiment and at the end, the scientists measured how much fat people had around the abdomen: there was no difference.
Another study looked at seasoned tennis players. The reasoning here was that if exercise reduced fat more on the body part being exercised, then tennis players should have less fat on the arm they usually play the ball with. And again: There was no difference between the arm dominantly used to play and the other.
Muscles Are Inefficient
Yet some people say, “hey, when I do these spot reduction exercises I can feel how that area gets hot”. That actually can be true, but it has nothing to do with using energy from fat cells in the area. Muscles, like conventional light bulbs, are simply not very efficient when it comes to using the fuel they get. Only 25% of what they receive they actually use to do what they are working on, the rest is given out as warmth. That is why muscles you work on feel warmer than others.
Exercise Trains The Muscle
Last but not least you sometimes encounter someone who did these exercises and is convinced it slimmed down the area in question. And again, these people may not be mistaken. It just is something different at work than they think.
If you are new to exercising, then doing a “spot reduction” exercise will make the muscle being worked on a bit bigger and the area in question may feel firmer. Doing a lot of these exercises of course also burns energy. If this is then combined with a reducing daily calorie consumption, you will lose weight and, if you are really lucky, that weight might actually come from the area you hoped to spot-reduce.
Yet It Does Work
I have to admit, one study did find that there might be an increased breakdown of fat from fat cells around a muscle being worked on. During 30 minutes of exercise this amounted to 0.6 – 2.1 mg (one mg = one thousandth g) more in 100 g of fat cells compared to other fat cells. Which means that to lose 1 g of fat from 100 g of fat cells on your tummy you have to do 500 hours of crunches.
For those of you who prefer hearing this in my endearing accent, here is a video: