The very basic exercises of any martial-art is more than enough to help you lose those excessive weight and fit into your gym clothes again. The stamina, strength and simplicity of these push-ups or horse-stance punches, etc ensure you can practice them anywhere you go; no gym needed at all.
Before you start kicking and punching though, let us know essential aspects before such physically demanding Karate movements. You may have noticed in the news how celebrities and other people aged between 35 and 45 years, who look physically & mentally fit, exercise regularly, are active in their profession, have suddenly dropped dead with a stroke.
Just because a person has a flat stomach does not mean they are not at a risk of heart disease. So, please visit your general physician and take adequate tests to check how much physical effort can your body tolerate in a day.
While at it, get your food intake recommendation as well. Needless to say, clean filter water is important part of daily 'nutrition' as well.
Now, how about the basic exercises ?
1. Toe-Touching: Stand erect. Make sure your spine is not hunched over and bring your shoulder blades at the back together. Now, keeping your arms parallel to each other, move them straight up, reaching for the sky, parallel to your ears. Then slowly bend forward, bringing your parallel arms in the downward direction. Keep your knees locked so that the knee-joints do not bend with your waist. With the fingers of both your hands, reach for your foot, but it is okay if you are only able to reach your shin bone at first try.
Don't force yourself to reach for the toes if your waist and locked knee do not enable it at present. In due time, with regular practice, you will not only touch your toes, but even touch your entire palm to the floor next to your ankle as in given illustration.
2. Waist Twisting: Keep your feet shoulder width apart. Keep your back straight. Place your hands on your hips. Now, slowly swing your upper-body to the right. Then swing it to the left. Make sure your lower body does not move and your feet are firmly planted on the floor. Developing this flexibility will give you lot of benefit in future martial-arts exercises.
These are illustrated below. Please consult a qualified trainer as these image/s are simply for illustrative & presentation purposes only.
Never start any exercise routine anywhere without first having a fitness certificate from a medical practitioner.