It can be pretty daunting to visit a gym full of muscular athletic males, brimming with testosterone, when you are still at the skinny, not too confident stage. Thats why many people crave such an athletic looking body, but cant bring themselves to join. For this reason, the advice below can all be followed in the privacy of your own home. Later on, of course, when you have created your own body to die for you can get down the gym with the rest!
Firstly, lets address the food issue. Eating a diet of junk food isnt going to work here. You need to start consuming high quantities of lean meat and fish and thats not from the fish and chip shop! In addition to that you must add lots of carbohydrates in the form of Rice, Pasta and Potatoes, accompanied by vegetable and fruit. Good fat is important, such as oily fish containing Omega 3. This will help to boost your immune system during heavy training. Also plenty of water is essential to flush your system through, clear out the toxins and keep you well hydrated, as during exercise you sweat out a lot of salts and minerals. Eating often throughout the day is beneficial as it keeps your metabolism regulated.
Now to exercise. Running builds up stamina in a very simple but effective way. You can use a treadmill, but it can be far more enjoyable to just get some fresh air and see some sights as you run along. This mainly builds up your legs, but also uses abdominal muscles.
Now to your upper body. Sit-ups or abdominal crunches, press-ups, weight lifting, squats and any form of resistance training is beneficial. Plenty of detailed information on these exercises is available. As you become stronger and fitter, increase the amount of weight you are lifting and the intensity of the exercises. If you miss sessions because you dont feel like it, or dont put much effort in, you will not get the results you want.
There is always the opposite end of the spectrum where you could do too much. This can be very dangerous as over-exercise releases Cortisol which uses muscle tissue and increases the storage of body fat. Around 45 minutes maximum of daily weight training should be sufficient to build up muscle.
Always take advice and proceed along a scientific and structured course. There is no instant fix that can give you a muscular body. It all takes time, patience and commitment.