Lifting weights is activity, and activity burns energy, which is one half of the weight loss equation. There are elaborate schemes target=ing enhanced weight loss, but all of them strike at one of the two parts of the weight loss equation. Either you're going to have to reduce the calories coming in or you're going to have to increase the number being burned by the body. Weight lifting is beneficial for a person's weight loss goals for two reasons: it burns energy and it leads to increased lean body mass.
When it comes to burning energy, lifting weights consumes primarily carbohydrates. The actual movements
Overall, you would burn a lot more total calories in one hour of aerobic exercise, compared with a one-hour weight lifting session. The efforts in weight lifting are so short, and the cumulative rest time between sets is so long, that the hourly caloric burn is not terribly great. At the same time, I'd rather see a person lift weights than skip working out all together, and combining strength and endurance training into a comprehensive program is a great way to reach your weight loss goals.
The other benefit to weight lifting comes from changes in body composition. As you gain lean body mass and lose fat mass, your overall body fat percentage drops. Your body has to use more energy to support muscle; so having additional muscle helps burn additional calories during the day. On a day-to-day basis, this increase in metabolic rate is barely noticeable, but over time it can add up.
Consistency is very important for gaining lean muscle mass. In the first 8-12 weeks of weight training, the majority of your progress is from your nervous system. You don't really start gaining significant muscle mass until after that. Also, after getting acclimated to a weight lifting program for a few weeks, focus on moving heavier weights for 6-8 reps per set, rather than light weights for a million reps. It's the maximum force you can produce with the muscles that stimulates them to adapt and grow. Light weights and many reps is more of an aerobic exercise that fatigues muscles. It makes you feel like you're doing a lot of work, but it''s work that's not doing much for you.