London: In a world, where being fit has become a 'mantra' for everyone, a balanced diet is the most essential thing people need to take care of.

And now a doctor has revealed that people don't need to sign up to a gym as a balanced diet of plenty of vegetables, fish, dairy and healthy fats can do wonders for their waistline, reports Daily Express.

Dr. Aseem Malhotra also revealed that people can maintain fitness with lots of brisk walking, says the top doctor.

Cutting sugar and refined carbohydrates, like cakes, pasta and pizzas, is also key to good health.

Dr Malhotra noted, "It is clear that diet and lifestyle are far more powerful than drugs or taking to the gym. Lifestyle changes such as consuming less sugar are more powerful than any medication doctors can prescribe. You cannot outrun a bad diet - this should be what doctors are advising their patients. Eating junk food and then trying to beat the bulge with heavy workouts is a waste of time."

Enjoying dark chocolate and a glass of wine in moderation, however, would be beneficial to health, said Dr Malhotra. He also explained that following a balanced diet and healthy lifestyle can transform a person's health in just 21 days, reducing the risk of heart disease and diabetes and increasing longevity.