The primary ways to lose weight (assuming abnormalities such as Thyroid Dysfunction etc. does not exist), are:
This is the PRIMARY FACTOR responsible for Weight Gain or Weight Loss.
You CANNOT OUT-EXERCISE A BAD DIET.
You need to ensure that you are on a Calorie Deficit…that is, Calories Consumed is LESS than Calorie Expended.
You also need to consider What Kind of Foods you eat, When you eat them, How much you eat and How you eat.
Eating too much of Sugary and Starchy Foods (Simple Carbohydrates such as White Rice, White Bread, Flour, Potatoes…) will lead to FAT Accumulation.
Eating too much food will lead to FAT Accumulation.
Eating too often without sufficient gaps will lead to FAT Accumulation.
Eating too Fast, will usually get you to eat More Quantity than Required, which will of course, lead to FAT Accumulation.
Keep an Active Lifestyle. This is the opposite of a Sedentary Lifestyle. Keeping Active will cause you to burn more Calories than will be Stored As FAT.
Proper Exercise will keep you Healthy and Fit.
Remember, ANY ACTIVITY IS WAY BETTER THAN NO ACTIVITY.
Having said that, Exercises and the way we do them, have varying effect on our bodies.
Weight Lifting, if done in the correct manner, will make you Stronger. Your Muscles get Stronger and Bigger…which leads to more utilization of Calories, rather than Storing these Calories as FAT.
Weight Lifting also causes your Bones to get Denser (which is GOOD…you don’t BREAK BONES, when you fall, for instance). This causes an Increase in Weight…which is Healthy.
Having Bones that are Less Dense, does translate to Less Body Weight… However, this will mean that they are WEAK and likely Quite Brittle. Such bones will Break/Fracture quite easily. This situation is therefore, NOT A HEALTHY one.
Weight Lifting is ANABOLIC (if done correctly AND with Proper Rest and Recovery AND through Proper Nutrition)…adds Muscle. This causes an Increase in Weight too…although, quite Healthy.
Becoming too frail is NOT a good thing, for many reasons…especially, as you get older.
Sprinting is quite different from Long Distance Running. I am assuming that you are referring to Long Distance Running (Marathons).
Long Slow Distance Running is Aerobic in nature. It is also CATABOLIC…whenever Protein (stored in our body), gets to be utilized for Energy, Muscle Loss happens. Think of all the world-class marathon runners and how they look (pretty frail).
So, a LOT of Long Distance Running, will cause loss of Muscle Mass eventually, and therefore, will also cause a Decrease in Overall Body Weight, (with Healthy Eating Habits).
Remember, we talked about ANY ACTIVITY IS BETTER THAN NO ACTIVITY?
Well, Walking is Better than Sitting in the Couch all day long and eating Chips and Sipping Coke, and doing nothing else (used here as an Extreme Example).
While too much of FAT is obviously Detrimental to Health, FAT is nevertheless, quite Important and Essential.
Also, studies have shown that to have about 15%-16%-17% FAT increases Longevity (Live Longer). People with Lower Fat (say, in the single digit percentages) tend, NOT to live as long. This is true, even for Diabetics and for people suffering from Heart Disease and such.
When you think of Losing Weight, keep all the above factors in mind.
Basically, you do want to Maintain a HEALTHY BODY WEIGHT, but ensure that this is due to your Increased Muscle Mass and due to Stronger Bones, and is NOT due to EXCESS BODY FAT.