1.You’re gaining muscle
If you’ve been working out, you may be gaining muscle and losing fat. When this happens, your clothes may start to feel looser — especially around the waist — despite a stable scale weight.
Measuring your waist with a tape measure and taking monthly pictures of yourself can reveal you’re actually losing fat, even if the scale number doesn’t change much.
Bottom Line: Many factors can affect scale weight, including fluid fluctuations, muscle mass gain and the weight of undigested food. You may be losing body fat even if the scale reading doesn’t change much.
2. Eating too many or too few calories
A calorie deficit is required for weight loss. This means you need to burn more calories than you consume.
For many years, it was believed that a decrease of 3,500 calories per week would result in 1 lb (.45 kg) of fat loss. However, recent research shows the calorie deficit needed varies from person to person
You may feel as though you’re not eating very many calories. But in fact, most of us have a tendency to underestimate and under report what we eat
In a two-week study, 10 obese people reported consuming 1,000 calories per day. Lab testing showed they were actually taking in about 2,000 calories per day
You may be consuming too many foods that are healthy but also high in calories, such as nuts and cheese. Watching portion sizes is key.
On the other hand, decreasing your calorie intake too much can be counterproductive.
Studies on very low-calorie diets providing less than 1,000 calories per day show they can lead to muscle loss and significantly slow down metabolism
Bottom Line: Consuming too many calories can stop you from losing weight. On the other hand, too few calories can make you ravenously hungry and reduce your metabolism and muscle mass.
3. Not exercising or exercising too much
During weight loss, you inevitably lose some muscle mass as well as fat, although the amount depends on several factors (8). If you don’t exercise at all while restricting calories, you’re likely to lose more muscle mass and experience a decrease in metabolic rate.
By contrast, exercising helps minimize the amount of lean mass you lose, boost fat loss and prevent your metabolism from slowing down. The more lean mass you have, the easier it is to lose weight and maintain the weight loss
Over-exercising can also cause problems.
Studies show excessive exercise is unsustainable in the long term for most people and may lead to stress. In addition, it may impair the production of adrenal hormones that regulate stress response .
Trying to force your body to burn more calories by exercising too much is neither effective nor healthy.
Lifting weights and doing cardio several times per week is a sustainable strategy for maintaining metabolic rate during weight loss.
Bottom Line: A lack of exercise can lead to loss of muscle mass and lower metabolism. On the other hand, too much exercise is neither healthy nor effective, and it may lead to severe stress.
4. Not lifting weights
Performing resistance training is incredibly important during weight loss.
Studies show lifting weights is one of the most effective exercise strategies for gaining muscle and increasing metabolic rate. It also improves overall body composition and boosts belly fat loss .
In fact, a review of 15 studies with more than 700 people found the best strategy of all for weight loss appears to be combined aerobic exercise and weightlifting (18).
Bottom Line: Weightlifting or resistance training can help boost metabolic rate, increase muscle mass and promote fat loss, including belly fat.
5. Overestimating how many calories you burn during exercise
Many people believe that exercise “supercharges” their metabolism.
Although exercise increases metabolic rate somewhat, it may actually be less than you think.
Studies show both normal and overweight people tend to overestimate the number of calories they burn during exercise, often by a significant amount (4, 20, 21).
In one study, people burned 200 and 300 calories during exercise sessions. Yet when asked, they estimated they had burned over 800 calories. As a result, they ended up eating more
That being said, exercise is still crucial for overall health and can help you lose weight. It’s just not as effective at burning calories as some people think.
Bottom Line: Studies show people tend to overestimate the number of calories they burn during exercise.