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Thursday, January 6, 2011

Exercising to Lose Weight is a Myth!

The Myth
There is a common assumption that one has to exercise more to lose weight.  This is based on a "calories-in versus calories-out" understanding of weight loss.  If this is true, take a good look at your gym.  Notice the folks who go several times a week but are still noticeably overweight or packing extra pounds?  Or perhaps you're wondering why you have trouble shedding weight even though you do cardio three times a week.  The truth is exercise alone won't make us lose weight.

Losing Weight
Losing weight is largely a function of what we eat and secondarily how much we eat.  How much we eat is governed by what we eat. Some foods leave us hungry faster than others.  Other foods keep us feeling full so our total caloric intake throughout the day is less.  A good book to understand this phenomenon is Gary Taubes' Why We Get Fat.

What Causes Fat Storage
When we eat sugar, sweet things, wheat, beans or legumes, it causes the body to release a lot of insulin into the bloodstream. Insulin is a hormone which tells the body to store the glucose (sugar) in the blood stream in the liver, muscle and fat cells in case we need energy in times of food shortage.  This was a good thing when food was scarce.  It is not such a good thing in our present times when there is sugar or refined carbohydrates readily available all around us.  It makes it too easy to eat foods which are quickly converted to sugar in the body and stored as fat.  Insulin is a fat-storage hormone. When insulin is released, it prevents the body from using fat as an energy source. This is why when a person drinks Gatorade before and during a workout, they do not end up burning fat.  Instead the body ends up using the sugar from the drink for its energy requirement during the workout.

The average human body stores between 1200-2400 Calories worth of energy in the muscles. The liver stores another 300-400 Calories of energy. However, visceral and subcutaneous fat stores about 100,000 Calories!  Clearly the body is programmed to store energy as fat whenever possible.  It is precisely this ability of the body to turn anything we eat into fat easily that works against us in a modern world where cheap, nutrient-empty calories are in abundance.

When we eat foods that do not cause high levels of insulin, our bodies burn fat for energy using a process called gluconeogenesis.  This is why working out in a fasted state enhances the fat-burning process.  Some might argue they won't have enough energy to complete a workout if they don't have an energy bar before or during the workout.  A 205 lb. person doing 2 to 3 hours of general aerobic exercise burns up to 2400 Calories (the same as the amount of glycogen in the muscles).  Remember visceral and subcutaneous fat?  You can't work off 100,000 Calories in one sitting. Still think we need that energy drink?

When we fast, we abstain from eating.  Since there is no food entering the body, insulin is not secreted and the body is not in fat-storage mode.  As energy requirements rise, the body releases glucagon which tells the liver to convert stored fat into glucose to feed cells with energy.  Insulin is then secreted to enable energy uptake by glucose-dependent cells thereby causing blood sugar to stay within a healthy range.  This part of a normal hormonal feedback system.

Turns out that eating healthy fats and protein increases satiety and doesn't cause blood sugar to spike as much as eating refined carbohydrates.  This means less issues with fat storage and less issues using fat as an energy source when the body requires energy.

What To Eat
For this reason, meals should consist of fats, protein and vegetables. A little fruit is OK. Foods to avoid are sugary drinks, starchy foods and grains (whole or otherwise).  If this sounds like an Atkins Diet, it is.  The Paleo\Primal Diet and Atkins Diet are similar but not identical. Just don't confuse the Atkins Induction phase with the Maintenance Phase. I won't bother dithering about the differences as either of these are better options than a vegetarian diet or a Standard American Diet.  If you're not sure whether the Atkins Diet is healthy, do some research here.  If you want the truth, watch this video from Stanford University.  If you don't have time, bookmark it and watch it another day.

Which Came First:  Exercise or Weight Loss?
That's me in the picture above.  I've been asked if I lost weight by cycling and kickboxing.  The answer is no.  I lost weight by changing my diet first.  I went from 170 lbs. at 5'6" to my present weight of 141 lbs - losing about 17% of my bodyweight. I began to exercise after losing weight.  After I lost weight, exercise became fun again.  Here is my skilled instructor Milo and I going at it for a 2 minute round. I'm in shorts.

If exercise doesn't make us lose weight, what does it do?  Exercise strengthens muscles, preserves the body's range of motion, increases cardiovascular capacity, lowers blood pressure and reduces the risk of coronary artery disease. It boosts metabolism and lowers stress. It stimulates testosterone and human growth hormone. It also improves one's sex life by improving blood flow networks all over the body.

Exercise alone however, does not make us lose weight.  That comes from changing what we eat.  The right kind of exercise partnered with a change in dietary choices is the key to the physical transformation most people seek.

To summarize, eating right helps us lose weight. Exercising makes us fit.


Update:  I came across an article in TIME magazine which concluded with:  "In short, it's what you eat, not how hard you try to work it off, that matters more in losing weight."

1 comment:

  1. If you are having trouble making your diet healthier, start by eating anything you eat slower A lot of people out there are fast eaters so they shove down.
    lose weight fast