Exercise is essential to losing weight. If you are serious about and truly committed to losing weight then you have no alternative but to increase your activity level.
Without exercise you will never be able to create your daily calorie deficit and without that you will not lose weight.
Don't limit your thinking when it comes to exercise. Exercise is any physical activity that raises your heart rate and keeps it elevated for at least 20 minutes. If you have the time to go to a gym then go, but if you do not have the time then be creative in how you achieve your weight loss exercise. Exercise = calories burned and that plus your reduced portion sizes and low fat meals means you will be losing all the weight you want.
Here are a few suggestions regarding exercise:
Start slow and build up. When you get to a comfortable level and feel you are doing everything you can add 10% more exercise to your exercise routine.
Don't create obstacles in your mind about exercise. You are not expected to be a world class athlete. You are expected to do everything you can to reach your weight loss goals so find as many ways possible to add activity and exercise into your day. Set your goal to burn 250 calories and work up from there.
Get the approval of your primary care physician before you get involved in a strenuous sport. If you rush into an activity that is too strenuous and makes demands on your body that it is not prepared for, you could injure yourself. Depending on the injury you could set yourself back for weeks.
You have to burn calories so find something that you enjoy doing and then the burning of calories won't seem like work.
Activities are always more enjoyable when you can share them with others.
Try to enlist a friend or family member to exercise with you. When you have support and you are having fun then there is a much greater probability you will continue with the activity.
Losing weight is a lifestyle change and exercise is part of that change. Make this a true lifestyle change and not a change just to lose weight.