Likewise, factors like age and body type can affect how fast you can shed extra pounds. Older people, for example, often lose weight more slowly, perhaps because of hormonal changes and/or because they have less muscle mass or may be less physically active.
So, if you're comparing your weight loss to someone else's, make sure you're not comparing apples to oranges (or pears)—that's just going to be frustrating and won't tell you anything useful about your own efforts.
Sometimes, though, people who seem to share a lot of these factors—similar body size, weight, age and activity levels—just don't get the same results, even when they do the same things. A lot of individual factors, including your individual genetics and quite a few medical conditions (like hypothyroidism, PCOS,and insomnia) and medications (like corticosteroids, or antidepressants), can make weight loss difficult. If you're in this boat, you may need to work closely with your health professional to find an individualized approach that will maximize your weight loss results without jeopardizing your health.
But more often, slow or non-existent weight loss can be traced to very common problems that can be identified and overcome with the right kinds of changes in diet, exercise, or daily activity patterns. That's what we'll be looking at below.
The No. 1 Problem: Your numbers aren't right.
In a healthy, "normally" functioning body, weight loss occurs when you use (burn) more energy (calories) than you take in from food. This calorie deficit forces your body to take fat out of storage and turn it into fuel that your cells can use to maintain necessary body functions. A pound of fat represents about 3,500 calories of stored energy, so you can predict that a calorie deficit of 3,500 will translate into one lost pound, give or take a little.
By far the most common reason why weight loss seems to be going slower than people expect is that their calorie deficit is not as large as they think it is. Either they're not burning as many calories as they think they are, or they're eating more than they think they are, or a combination of both.
The formulas used to estimate how many calories people need to maintain their current weight aren't accurate for everyone—they can be off by as much as 30-40%, especially if your body fat percentage is pretty high, your physical activity level is significantly higher or lower than average, or you're counting almost everything you do (e.g., light housework, grocery shopping, walking up one flight of stairs) as "exercise" even though it doesn't actually meet the parameters of what counts as fitness (a high enough intensity to elevate your heart rate to an aerobic range; a duration of at least 10 continuous minutes for the activity; the moving of large muscle groups in a rhythmic way).