I believe that you need both 'exercise' and 'activity' along with 'intake' control to lose or gain weight.
For me activity is the stuff that you do every day like walking to the store, climbing the stairs instead of taking the elevator (or just deciding to carry the stuff upstairs in 3 runs instead of 1), gardening, shoveling snow etc.
Exercise is intentional high intensity activity that you work up a sweat (even mild) doing.
Aerobic activity like walking, running, biking, skating, swimming etc help you to burn calories and build up your cardio resistance and lung capacity. Anaerobic activity like weight lifting, resistance training, work with elastics, pilates etc help to build up muscle.
Some of these exercises do both (think kick boxing).
Both are important for optimum health and you should do both according to your level of health and ability as well as age. ( I avoid anything that puts too much stress on my joints or has me jumping up and down).
If you incorporate even 10 extra minutes of activity and 10 of exercise into your daily routines you will see slow but steady results. Add to that 10% less calories (1 bag of chips or a chocolate bar less a day for example or baking your food instead of frying it) and you will see even faster results,
Weight loss does not have to be dramatic or painful. Sometimes small changes can have big results over time.
I hate diets so I never do them...instead I increase output (exercise & activity) and decrease my intake (more fruits & veggies and less ice cream or jello instead of snackfoods) to control my weight.
It has worked for me for most of my life...right now I am at a near high in weight ( about a size 10-12) but have been working out 2 hrs/day including 1hr of treadmill strait uphill on a 3mile/hr pace (walking, not running) and or swimming and water aerobics (easier on the joints)...I have not lost much weight but have gone down a full size in 2 weeks.
If I could just get control of my ice cream habit I would be melting!
I've been coaching diet/exercise in my executive coaching practice for over 25 yrs now and find that the best results are always those that go slow and steady and integrate gradual change into your lifestyle.
Do not neglect your vitamin/minerals and hydration...not enough hydration and you will be too tired to work out.
Sharon