When it comes to weight loss, there are many factors that influence how fast or slow someone loses weight. Everyone is different, and that is one reason why people want more of a clear cut answer how long weight loss takes.
Unfortunately, there is no magic guarantee how fast weight loss can happen. There are estimates we have in place to guess how long it may take to lose 20 pounds, but it may be faster or shorter than what we expect.
Here are some general guidelines and estimates for how long it can take to lose 20 pounds. However, keep in mind these are only estimates, and there is high individual variance.
Most weight loss websites will tell you in order to lose a pound of fat, you need to be in a calorie deficit of 3,500 calories. This is an estimate of how many calories there are in a pound of fat, and this number has been used for many years.
Recently, some health professionals are questioning how accurate the 3,500 calorie per pound estimate is, but never the less it can be a good starting point for mapping out your weight loss. Common advice is to cut out about 500 calories per day through a combination of diet and exercise.
You can determine your baseline calorie needs from many fitness apps and/or websites (or use our BMI Calculator) that all use a common equation to determine someone’s calorie needs.
From that number you can subtract about 500 calories per day to determine a calorie goal during weight loss, assuming it doesn’t go below 1,200- 1,000 calories per day.
Quality and quantity
Other starting tips include focusing on calorie quality, not just calorie quantity. If your target weight loss calorie intake is 1,200 calories, you still need to focus on making sure those calories are providing your body with nutrients and not just sugar or preservative filled food.
Focus on getting a high amount of fruits and vegetables for weight loss; this will also help you fill up on the right type of food.
Some people like to focus on the calorie numbers, and some people don’t. For those people who don’t want to focus on the numbers, focus instead on quality of your calories. How can you change your diet so you are eating foods in their most natural forms?
1-2 pounds per week
What’s a short answer for how long it takes to lose 20 pounds? In general, a quick estimation would be 10-20 weeks. This is based on the assumption that someone is losing 1-2 pounds per week, as recommended by the Center for Disease Control and Prevention (CDC).
Losing 1-2 pounds per week is a reasonable weight loss suggestion and can be maintained long term. It is also generally recognized as a safe approach to weight loss. Using the example above, losing a pound a week may equal a calorie deficit over a week of 3,500 calories (500 per day). Therefore, a weight loss of 2 pounds per week would be more like 1,000 calories per day.
Faster than 10 weeks?
Can you lose 20 pounds faster than the CDC guideline of 1-2 pounds per week? It can be possible. The more weight you have to lose, the easier it is to lose more than 1-2 pounds a week. However, usually as weight loss goes on longer term, weight loss can become harder. Remember, everyone is different, and some people can naturally take extra weight off quick with some lifestyle adjustments.
Factors that can speed up or slow down weight loss
Genetics can have a role of weight regulation that is hard to impact. The weight loss equation of subtracting 500 calories per day doesn’t take this into account. Hormone levels, age, muscle mass, sleep amount, stress level and gender also influence body weight regulation outside of diet and exercise.
Another factor with losing weight is consistency. Losing 1-2 pounds consistently over 10-20 weeks can be challenging, but the more you stick with your lifestyle changes the more you will probably be successful. If you veer off of healthy food intake and adequate exercise, losing 20 pounds can take longer than 10-20 weeks.
Weight loss has a lot of variables and every human body has differences how it controls body weight regulation. A general guideline for weight loss is associating a pound with fat to 3,500 calories. Therefore, weight loss of a pound a week would take a calorie deficit of 500 calories per day.
A general guideline for losing 20 pounds based on weight loss of 1-2 pounds per week would be 10-20 weeks. Many factors could increase or slow down this time length though. Some other factors besides calorie intake and exercise that affect weight balance include hormone levels, age, lean mass, gender, stress levels and sleep patterns.
References used in this article