How to Get Fit Fast if You Are Thin

Consume a healthy diet that includes lean proteins, fresh vegetables and fruit, whole grain products and low- or nonfat dairy to provide your body with the nutrients and energy you need. Limit sweets or junk food to once in a while, rather than eating them daily.

Drink plenty of water, eight to 10 glasses daily, to keep your body hydrated during the day and while engaging in exercise.

Participate in a minimum of 150 minutes of cardio per week for good heart health. Choose aerobic exercises you enjoy, such as walking, riding your bike, taking a class at the health club or playing tennis with a friend. Break up your cardio workouts however you need to fit your schedule. Exercise for 10 minutes three times per day or 30 minutes once each day as needed.

Perform strength-training exercises two to three times per week for 20 minutes per session. Include exercises that work your upper and lower body muscles, as well as those in your core. Use dumbbells or kettlebells while doing biceps curls, triceps kickbacks, and shoulder and chest presses. Work your core muscles by performing seated trunk rotations with a medicine ball. Tone your legs and glutes with squats, lunges and leg lifts.

Stretch after each workout to prevent muscle soreness and increase flexibility. Perform stretches for five to 10 minutes, including toe touchers, reaching for the sky and the overhead reach side bend. Stand straight while extending your arms above your head. Place your hands together, and bend at the side as you lower your upper body toward the left. Stop when you feel a stretch along your right side, and hold the stretch for 10 counts. Repeat on the other side.