In order to lose weight and stay fit, do I have to be on a diet or is it okay if I just exercise?

Out more than in. In order to lose weight, you need to burn more calories that you eat. In order to stay fit, you need to exercise at least 20-30 min several days a week. Beyond that, it totally depends on what your goals are, where your weight is today and where you want to be.
Exercise more? Yes, it is possible for you to lose weight by just exercising more. If you consume the same amount of calories and increase the amount of exercise, thus boosting your metabolism and burning off more calories you will lose weight. However, the most effective way to effectively lose weight is a combination of improving your diet, eating less calories, while increasing your activity level as well.
Both. Both a healthy diet and regular exercise regimen are important when attempting to lose weight and stay fit. Sometimes, consultation with a nutritionist and/or work with a personal trainer may be helpful. Best wishes.
NO. You do not have to be "on a diet" however a healthy balanced diet and a lifestyle of choosing healthy foods is essential for lifelong fitness in addition to exercise on a regular basis. Avoid fried foods, foods high in sugar, and processed foods as much as possible.
Weight. In order to loose weight, u have to watch what u eat, how much u eat and u need to excersize. Try to eat more fruit, vegetable and refrain from eating junk food. In addition drink water instead of juice and have a regular exersize.
Eat better. Studies show that eating better and less is more effective than just exercise alone. Exercise is important for weight loss maintenance. Also if you increase your daily non exercise time by moving around more, you can burn more calories. Eating better is not a diet but a lifestyle. Calories consumed must decrease with age due to decreasing resting metabolism rate from loss of muscle.
2 things. To stay fit, you need exercise. To lose weight you need to burn more calories than you eat/drink. Simple math will work. No need to diet if you burn more than you eat. Speed of weight loss is linked to the difference in the calories. Good health is also linked to a good diet. Diet here means eating right not "dieting". Good luck.