Diet and exercise must be combined to achieve weight loss goals, according to the study.

The research was conducted on 18 female rhesus macaque monkeys. They were fed high-calorie diet for several years, then given a 30 percent reduction in calories.

Not only did they lose no weight, but physical activity levels for the monkeys began to drop shortly after the reduced-calorie diet was introduced.

Another comparison group of three monkeys was trained to exercise for one hour daily on a treadmill. This group did lose weight. (American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, April 2010)

Dr. Mercola's Comments

In the modern day, however, this innate process may backfire, causing you to hold on to excess weight if you do not consciously make an effort to increase or at least maintain your activity levels.

Further, although low-calorie diets have been highlighted as a strategy for lengthening your lifespan, if you simply cut way back on calories without meeting your body’s nutritional requirements, it can send you into starvation mode. This will actually slow down your metabolism and make it more difficult to lose weight.

Exercise alone may also not help you lose weight, especially if you’re “rewarding” yourself for working out by eating an order of French fries accompanied by a chocolate shake.

The key to healthy weight loss is to use a combined approach of both diet and exercise together. This is the strategy that will lead to gradual weight loss and a healthier lifestyle that you can actually sustain and live with.

A Lack of Activity is Detrimental to Your Health

Whether you’re trying to lose weight or not, regular physical activity simply must be a part of your life if you want to stay healthy. This is true even if you’re eating a stellar diet, and whether you’re overweight or not.

In fact, one study published in the Journal of the American Medical Association found that women who were at least somewhat active were less likely to develop heart disease than those who were not, and this was regardless of their weight.

Another revealing study also found that both diet and fitness levels are crucial for lifelong health. After analyzing more than 115,000 nurses, results showed that being overweight or being sedentary increased your risk of death independently:

•Women who were obese and inactive had a 2.5 times higher mortality rate than women who were lean and active

•Those women who were active (despite being obese) were twice as likely to die a premature death than those who were lean and active

•Lean women who exercised under 3.5 hours a week increased their risk of premature death by 55 percent, compared to those women who worked out more often

•Obese women who worked out for at least 3.5 hours a week experienced a death rate that was 91 percent higher than lean women who exercised similarly

•The premature death rate was 142 times greater for obese, inactive women

So while being overweight or obese certainly increases many health risks, those who were lean and inactive also had their share of risks. And as you might suspect, the most significant risks apply to those who are both overweight/obese and also sedentary.

The moral of the story, of course, is that you want to carefully tailor both your dietary and your exercise habits in ways that will support your health and well-being.

Why Many Forms of Exercise Don't Work Very Well

As many of you know, I have been an exercise fanatic for the last 42 years. Life is a journey and I certainly made a load of well intentioned mistakes over those years. It is my goal to help you understand some of those mistakes so you don't have to make the same ones I did.

My major mistake was that I focused nearly exclusively on cardio. I focused on running and actually did fairly well competing as I ran a 2:50 marathon and a sub 5:00 minutes mile. However, even though I was aerobically fit I virtually ignored anaerobic training after I stopped competing 25 years ago.

Turns out that is what most people do. They stop doing speed work when they get older. Most exercise works just fine for most people so long as they are under 30 years old. At that time one’s growth hormone dramatically starts to drop.

A better name for growth hormone would be "fitness" hormone. It is the strongest influence on increasing your muscle mass and reducing your body fat. That is why many people inject it illegally. Fortunately with the right type of exercise, your body can produce it naturally.

Super Fast Muscle Fibers

It turns out that nearly ALL exercises that are typically done in this country by those over 30 do not generate growth hormone. This is because they are not exercising the super fast muscle fibers. Cardio, aerobics and even most all strength training do NOT increase growth hormone. The only way to do that is by using anaerobic exercises or speed work. You have to push REALLY hard and work intensely for brief periods of from 10 to 30 seconds.

These are typically sprint type of workouts but they don’t have to be done by running. You can do them on many pieces of aerobic equipment such as a treadmill or bike. One of the best is a recumbent bike.

The principle is simple. You warm up for two minutes then increase your intensity level to as high as you can and pedal as hard as you can for 30 seconds. If you can pedal for 45 seconds you are not working out hard enough. You simply have to push it very hard.

After your 30-second workout you pedal at a comfortable intensity and relaxed pace for 90 seconds to recover, then you repeat this 7 times for a total of 8 cycles. If you are doing it correctly you will be sweating profusely, and it will likely be one of the best workouts of your life. Remember you have to work out intensely as you possibly can. If you aren't sweating very profusely and really gasping for air at the end of the workout you aren't cycling fast or hard enough.

The beauty of this approach is that it only requires FOUR MINUTES of exercise and only a total of 20 minutes of your time. If you do it properly I can assure you that it will improve your health far more than HOURS of regular cardio.

For the two hours following your exercise you will radically increase your level of growth hormone too, as long as you avoid sugar. This will tremendously help you to lose fat and gain muscle.

This really is some radical new information that can change your life. Once I started doing this I was able to easily drop extra weight I had picked up and could not lose despite doing my standard cardio. You can even apply this to strength training and rather than exclusively exercise your slow muscle fibers, like all cardio does, you can use explosive lifts and exercise your fast muscle fibers.

This is a bit challenging to describe in text so I hope to shoot a video on it soon so I can actually demonstrate it for you..

The master educator who taught me this was Phil Campbell and his term for it is Sprint 8. I recently met him at a fitness camp in Mexico. He has a book where you can get more information on this phenomenal form of exercise; it's called Ready Set Go.

I plan on introducing more detailed articles on this in the future.

Other Tried-and-True Weight Loss Tips

Everyone’s metabolism is different, but you can speed it up or slow it down within a reasonably short amount of time by making the following commonsense changes to both your diet and lifestyle:

•Eat according to your nutritional type to ensure your body is getting the right fuel it needs

•Avoid sugar, especially fructose and grains as they are the leading cause of insulin- and leptin-resistance, which affects your hunger levels, your weight, and your risk of any number of diseases

•Listen to your hunger, and eat a healthy meal or snack when hunger calls

•Implement a well-rounded exercise regimen that includes strength training to build muscle, as well as interval training, which has been demonstrated to significantly increase fat loss