In a word, no. Walking alone will not get you to lose weight. If you don’t change what you eat, you are not going to lose weight. You will get stronger, and your heart will benefit a bit, but it will not get you to where you want to be. The only way to do that is by changing the food you eat from whatever it is you eat now to something healthy. Period.
If I had a nickel for every person who told me that they were starting their new, healthy lifestyle by walking, I’d be retired. I always ask, “And what diet changes are you making,” to which I’ve been told without exception, “Oh, I’m eating moderately. The same food; just not as much.” I usually just nod and tell them, “Good luck!” No, I don’t do so sarcastically; I’m sincere. I really wish them good luck, because they will need it.
Weight loss is 90% what you eat and 10% exercise. Now, if you want to maximize your weight loss and increase your heart health and fitness, then yes, exercise is absolutely necessary and beneficial. However, it’s not necessary to exercise to lose weight. I lost 110 lbs in a year without a single step of exercise. I know it can be done because I did it.
If you’re going to start something, start with changing your diet. You will have much better, quicker, and long-lasting results than by walking alone. I know this from first-hand experience, too. Sadly.