Although regular workouts certainly play an important role in maintaining a healthy weight they are NOT crucial for losing weight.
What is crucial for losing weight is eating less, plain and simple. If more calories are consumed than used for energy no amount of time spent working out will lead to weight loss.
By all means, anyone looking to lose weight should exercise 3-4 times a week for about 1 hour, but it’s very import to reduce the number of calories consumed on a daily basis. This can simply be done by eliminating sodas and other sugary drinks or by eliminating sweets from one’s diet.
Keep in mind that you won’t lose weight either if you reduce the number of calories you consume but don’t exercise. The ideal combo is to eat less and exercise more, but eating less is a more significant factor in this formula.