Unfortunately "full workout" is not an objective term for judging workouts.
For me I'd have to walk for about 10 hours to burn enough calories to make me happy. For you that may be 30 minutes.
Depends on how fast you walk, the surface, the incline (or lack of), etc.
A walk is not a "full workout", IMO. It'll get your HR up if done correctly but it's not going to burn a significant amount of calories unless you do it for a very long time.
(A "normal" speed walk probably burns 150-250 calories an hour)
Walking it s a good start, IMO. It was what I started with when I had no activity in my life and something I like to keep up in combination of working out :)
I started off 10-20mins walks to 30mins walks to 40-60mins+ walks daily. Then implemented stationary bike 20-40mins, the weights and treadmill on an incline 40-60mins and casual 10-15mins walks instead.
I had a break and trying to get back into the swing of things, 15-30mins walks with stationary bike for 20-30mins or a about a hour walk on a trail of a local park (up and down hills, decent pace) and strength training.
Calories wise it burns decent amount of calories but not lots like other workouts or activity.
Health vs. Fitness model of exercise. You can realize most of the cardiovascular health benefits from walking at 50% of MHR for 25 minutes 2xweekly, that isn't going to do much for you in terms of cardiovascular fitness but you'd get started which is the most important thing.
Now, a reasonable program for you depends very much on what your current level of fitness is, and what sort of goal you have. Health,all-round fitness, sports performance, appearance? Most of those do have a large amount of carryover so you'd be doing roughly the same thing regardless, but it helps to know where you're starting from.
You can definitely lose weight and improve your health by walking. Yes, walking does burn calories, a lot of calories if you walk long enough and fast enough.
I strongly recommend that you record duration, distance, and frequency. If you have access to a spreadsheet such as Excel, all the better. If not, find some other place to log your workouts.
Slowly but steadily increase distance and time spent walking, until you achieve your goals.
In my opinion, a "full workout" walking means you are breathing hard by the time you are done; and your legs, for sure (and maybe even your arms, depending on how you move them when you walk), should feel "worked."
If you find that you like vigorous walking as your primary form of exercise, then down the road, so to speak, you could buy a good Heart Rate Monitor and use that for monitoring calories and recording exercising.
check out runkeeper.com this site track your walking and you can even plot your map of where you walked and how long. So far i've lost 15lbs from walking fast,uphill, keeping my heart rate at an average of 151bpm for 1 hr daily!
I lost a lot of weight several years back (80 lbs) by walking for an hour 6x a week along with a better diet. You can definitely lose weight that way.