^^^Good luck, I have 10 pounders on each leg right now. It took me 2 weeks before I could even walk straight, let alone walk down stiars, and that was just with the starting weight of 6 pounds on each leg. Though I have to say, theres been a definite improvement on my leg muscles. I can actually flex my quads, sorta. It's such a morale booster. My calves were always good though, what with me being hispanic.
Anywho, this has all been said before but repitition is good. For starters, stop having three big meals a day, if you do. It's why most of Americans are fat, we have too many big meals. Instead, have many small meals spread throughout the day, consisting of a little of each food group. This keeps your metabolism from slowing down, so that you can burn the food off quicker. I also recommend only eating fruits on an empty stomach, such as when you have your first meal. If you eat fruit and you already have food in there, the fruit will start to rot before it can be digested. Also, try healthier alternatives to foods. You should always drink fat-free or skim milk, they're the same thing in terms of fat content. Try eating more beans and nuts instead of meat, as meat can contain alot of fat. Beans and nuts are also as good as meat for protien. Peanut butter is good, but it also has alot of calories, so make it more of a treat/once a day thing. To avoid hunger pains, make sure you eat a few amounts of sugars followed up by protien, as protien takes longer to process. Dark, greeny vegetables are your friend. Bread as a whole is kinda iffy. Great source of carbs but white bread is just bread thats been bleached. This makes it insanely unhealthy. Instead, try to eat whole-grain/wheat. After your body gets used to the new diet, you'll find yourself getting full quicker and you'll be hungry less often, as you'll be getting all the nutrients you need in smaller portions.
As for exercise, considering you want a marathon, you should first work on losing some body fat and gaining some leg muscle. Swimming laps is a great way to do both at once. Other than that, running is pretty much the way to go. Doing squats willl help to build up muscle. I also suggest to start doing sit-ups/crunches and at putting at least a little bit off effort into your arms. This should increase your upperbody strength, vital for having good overall health. Once you've lost enough fat/built up enough muscle, I suggest working on conditioning your body and improving your endurance. Cardio is perfect for accomplishing both of these. Once you feel you've reached the level you were hoping for, I'd begin practicing to run the length of the marathon, if you haven't already. Yeah it's alot of work, and alot of times the pain and sacrifice will make you question if it's really worth it. There have been times where I couldn't bend my arms for two days because the strain was just too much. But in the end, you will fill a sense of accomplishment knowing that you did what you set out to do. And that feeling is better than anything in the world. Plus, hot chicks never go for fat dudes, unless they have like personality or some shit, so there's motivation right there.
