You just put down cash for a gym membership -- or maybe a trainer and a slew of exercise videos. How fast any of these routines will help you lose weight, though, depends on multiple factors, some of which are out of your control. Exercise, when coupled with a proper diet, can help you lose weight 30 percent faster than dieting alone, reports PubMed Health. Weight loss, though, is a complex process that can't be predicted with precision in women (or men.)
Estimating Calories Burned
In theory, if you burn off 3,500 calories more than you consume in a week, you'll lose a pound of weight. That means five or six sessions that burn between 580 to 700 calories each. The problem is that you can't be sure how many calories you actually burn with your exercise routine or how many you burn daily. Gadgets, machines and websites can give you estimates, but these are only a range and may be inaccurate. As a result, determining exactly how fast you'll lose weight with your routine isn't all about simple calculations. Your size, age and intensity all factor into how many calories you burn per hour of exercise. Women tend to burn fewer calories in an exercise session and all day long than men due to their naturally lower muscle mass and smaller size.
But, You Have to Consume Less
Even if you manage to burn off those 3,500 calories, you have to make sure that you've created a calorie deficit. If you use exercise as a license to eat, you won't drop weight at a very quick rate. In fact, if you overeat, you'll gain weight no matter how much you exercise. For example, if you burn off 3,500 calories in a week but eat an additional 1,200 calories in workout snacks that you wouldn't have otherwise, you're only at a 2,300-calorie deficit, and your rate of loss won't even reach 1 pound per week. As you lose weight, you burn fewer calories in each exercise session, and it takes fewer calories to maintain your weight. In turn, your rate of loss slows down, making calculating your exact rate of loss even harder.
More Complicating Factors
The more weight you have to lose, the faster exercise may help you drop pounds. Likewise, the less fit you are, the greater impact exercise may have on your rate of weight loss because you are inefficient and burn more calories than your fit friends. The changes you do, or don't, make to your diet will also affect your rate of weight loss. If you cut calories and exercise, you can lose more weight than if you only cut calories or only exercise. Being a woman makes figuring out your rate of weight loss even more challenging since hormonal changes and water retention can artificially boost numbers on the scale. If your exercise routine involves heavy weight training and you're putting on a fair amount of muscle mass, the scale may not reflect rapid weight loss even though you're losing fat. In this case, you're simultaneously gaining muscle, which is more dense but takes up less space than fat.
Flaws in the Equation
The theory that burning off 3,500 calories results in a pound of weight loss also has its flaws. A 2012 issue of the "American Journal of Physiology" conducted a study that divided participants into non-exercisers, moderate exercisers and frequent exercisers. The researchers found that people who exercised the most in 13 weeks -- about 60 minutes per day -- did not lose as much weight as the 3,500-calorie equation would have predicted, while the moderate exercisers -- who did 30 minutes per day -- lost the most weight, more than the 3,500-calorie equation would have predicted. This just goes to show that weight loss is more complicated than what you can compute with pen and paper and the rate at which you can lose weight with an exercise routine isn't an exact science.
Instead of focusing on a specific rate of loss, focus on the positive health impacts of adopting a regular exercise routine. Pay attention to the way your clothes fit and your image in the mirror rather than the numbers on the scale. Often, these external factors are a better reflection of your exercise efforts. Even if exercise doesn't yield a speedy rate of weight loss, know that you're putting yourself in a better position to keep the weight off once you do lose it.