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How long does it take to lose weight?

Written by John Davis

Last updated: September 9, 2022

Losing weight can have dozens of benefits for both your mental and physical well-being. Yet, it’s a process that usually takes time and ends up testing most people’s patience. 

Understanding how long it takes to lose weight and setting realistic expectations can significantly help boost your motivation. By maintaining focus, you can avoid common pitfalls of dieting and make the process much more enjoyable. Here’s what you need to know.

How Does Weight Loss Work?

The first step one should take after deciding to lose weight is to choose the proper dietary plan for your goals. Particularly, people who want to lose weight fast usually opt for very low-calorie diets, low-calorie diets, or intermittent fasting.

Yet, before starting with the program, it’s important to understand how weight loss works so you can set realistic expectations. Grasping the essential aspects of weight loss will allow you to make better diet decisions and help you maintain focus.

To completely understand weight loss, you must first get a hold of what calories are. Calories describe the amount of energy that a certain amount of food or drink holds (1) — for example, the average banana contains about 110 calories (2). 

Men need, on average, about 2,500 calories a day to keep their bodies at a healthy weight. Women, instead, need about 500 calories less, but the exact number will depend on a series of factors (1).

By taking in calories through food and drinks, we are essentially putting energy into our bodies. The body will later use it in everyday movement, spanning everything from jumping to breathing. 

However, when the intake of calories isn’t enough to cover the energy you use during the day, the body has to resort to using fat and muscle instead. This mechanic, called a caloric deficit, forms the main logic behind weight loss — burn more calories than you consume. There are three main ways to do this:

  • By eating less caloric food, hence lowering the caloric intake
  • By exercising more, therefore increasing caloric expenditure
  • A combination of both

Yet, in all three cases, it’s essential to understand that there are healthy ways of losing weight and not-so-healthy ones. A common mistake when losing weight, for example, is aiming to lose too much too quickly instead of letting the body go at a healthy rate.

How Long Does It Take to Lose Weight?

As with most things in healthcare, there isn’t a set, fast-acting weight loss diet that’ll work for everyone. Rather, the time it’ll take to lose weight will depend on several factors, ranging from age to medical conditions. By understanding the most crucial aspects, you can outline an efficient plan to lose weight — hence setting realistic expectations.


Research has shown that older people have a more challenging time losing weight due to a shift in their resting metabolic rates (RMR). RMR describes the number of calories the body burns when not doing physical activity. As one ages, the body starts using fewer and fewer calories for everyday movements, making it harder to reach a caloric deficit only through burning calories (3).


It’s known that women, due to biological differences, usually have a higher fat-to-muscle ratio than men. This causes the body to have a lower RMR, driving a lower baseline of caloric expenditure. So, following the same diet, a man will lose 5 to 10% more weight than a woman (4).

Initial Weight

While it may not seem obvious, your initial weight when starting a diet plan is crucial to the expected weight-losing speed. Larger people have more muscle due to their body frame, resulting in a higher RMR. Naturally, these muscles will be reduced over time, decreasing the metabolic rate (5).

Caloric Deficit

The caloric deficit proposed by your diet is probably the most crucial factor in calculating your weight loss rate. A higher caloric deficit will result in quicker weight loss, whether you achieve this by eating less or by exercising more. However, it’s important not to go overboard with this — a caloric deficit that’s too high may have serious side effects.

Other Factors

Although experts usually regard the previous four points as the most critical factors in weight loss, there are other things to keep in mind when considering weight loss rates. Unfortunately, you can’t control some of these, but being aware of them will help you create an ideal dietary plan. Here are some of the other factors that affect weight loss rates (6):

  • Family history
  • Genes
  • Ethnicity
  • Quality of sleep
  • Medications
  • Medical conditions

How Fast Can I Lose Weight?

While no set safe weight loss rate works for everyone, experts usually recommend aiming to lose no more than two pounds per week (7). Setting achievable goals every week will help you stay focused and motivated. After all, no diet will be good enough if you can’t stick to it for more than a couple of weeks.

However, some people still choose to aim for drastic diet plans that only allow for a daily intake of 800 calories or less. Consuming such a low amount of calories is not only unsustainable for most people but also dangerous, as it can lead to several side effects (8).

For example, one of the main concerns with these low-caloric diet plans is gallstones (9) — small, hardened stones that form in the gallbladder. These stones can cause other complications, such as cholecystitis and biliary colics (10). 

Other side effects that come from losing weight too fast include (7, 11, 12):

  • Losing muscle
  • Slowed-down metabolism
  • Nutritional deficiencies
  • Dizziness
  • Dehydration
  • Muscle cramps
  • Irritability

What’s the Fastest Way to Lose Weight?

Unfortunately, there isn’t such a thing as a fireproof way to lose weight fast. Experts instead recommend sticking to achievable goals, such as losing two pounds a week. While this may not seem like much, keeping up that goal for a whole year would allow you to get rid of over 100 pounds. 

However, specific reasons may call for faster weight loss, allowing the use of more drastic dietary plans. Here are some of the quickest ways to lose weight (13):

Very Low-Calorie Diets

VLCDs, or very low-calorie diets, are eating plans that only allow fewer than 800 calories per day. Such drastic programs usually lead to losing between 3 to 5 pounds a week. However, VLCDs should only be attempted under the strict supervision of your healthcare provider to avoid the previously mentioned side effects (13).

Low-Calorie Diets

LCDs, or low-calorie diets, are the softer versions of VLCDs — they allow similar benefits without most of the side effects. By limiting the daily caloric intake to about 1,200, LCDs will still cause a significant weight loss rate while also being overall easier to follow (13).

Intermittent Fasting

Fasting has had a resurgence in modern times thanks to its outstanding efficiency when it comes to losing weight. While there are hundreds of different fasting regimes, one of the most popular ones is the 5:2 system — fast two days a week and eat the other five. Fasting leads to rapid weight loss and is usually sustainable once you get into the habit (13).

How Do I Avoid Regaining Weight?

Maintaining the newly achieved success is just as important as the actual weight loss. Regaining weight is demoralizing and a common pitfall of weight loss — this leads to a cycle known as yo-yo dieting. However, paying attention to the following things will help you maintain your newly-achieved weight (14):

  • Setting a realistic eating pattern
  • Getting about an hour of physical activity throughout the day
  • Continuously monitoring your weight
  • Asking for the support of friends and family members

If you have trouble keeping weight off or going on a diet, you may want to check with a nutritionist. A trained professional can give you helpful weight loss tips based on your current situation, considering your personal factors. Plus, it’ll serve as an encouragement to keep your newly-achieved weight.

Key Takeaways: Losing Weight Fast

Although many factors, such as age and sex, can affect the rate at which you lose weight, the general formula still applies — spend more calories than you consume. However, it’s also crucial to set realistic goals for losing weight to be able to sustain your diet for long periods of time while avoiding other popular weight loss myths.

Experts agree that a safe rate for losing weight is about two pounds per week. You can achieve this through various tactics, such as low-calorie dieting and fasting. Regardless of how you choose to do it, remember that keeping weight off after the diet is just as important as weight loss itself.


John Davis