Rapid, short-term weight loss may lead to the loss of muscle mass, nutrient deficiencies, or gallstones. For safe, manageable, and long-term weight loss, aim to lose 1 to 2 pounds weekly.

Losing weight is a goal that many people have. While you may want to lose it as quickly as possible, it’s important to remember that weight loss is a journey that takes time, patience, and consistency.

Healthcare professionals recommend setting a weekly weight loss target of 1 to 2 pounds (0.45 to 0.9 kilograms [kg]), as this has been shown to promote safe, effective, and sustainable weight loss.

Losing more than that is generally considered too fast and may increase your risk of developing some health problems, including muscle loss, gallstones, nutritional deficiencies, and a drop in metabolism.

Keep reading to learn more about rapid weight loss techniques, their possible risks, and how to lose weight sustainably.

Many factors can influence how fast and where you lose weight, and each individual’s weight loss journey is unique.

Some of these factors, like genetics, age, and hormonal fluctuations, are out of your control. However, a slow and gradual approach to weight loss is recommended for almost everyone.

One of the most important aspects of weight loss is maintaining a calorie deficit over time. A calorie deficit is when your body expends more calories than you consume daily.

Many proponents of rapid weight loss claim that you can lose up to 10 pounds in 1 week. This usually includes a very low calorie diet of only 800 calories and getting plenty of exercise to create a very large deficit.

While a severe calorie restriction may cause a decline of more than 2 pounds on the scale during the first week, it’s important to note that this weight isn’t fat mass. Instead, it’s most likely “water weight.”

When you consume fewer calories than your body expends, your body uses its stored energy, known as glycogen. Glycogen is stored in your muscles and liver, and it retains water. Each gram (g) of glycogen retains about 3 g of water.

So, when you’re primarily burning stored glycogen for fuel, such as during your first week of a calorie deficit, the body is releasing that water. But this water weight can easily be replenished when you increase your calories.

If you’re on a very low calorie diet, the odds of reverting back to old eating patterns and regaining that weight are very high. This is often referred to as yo-yo dieting, and it’s not sustainable.

Weight loss is not simply about losing weight but about maintaining it long term. To do this, experts recommend aiming for a daily calorie deficit of 500 to 750 calories, which roughly equates to 1 to 2 pounds weekly.

You may still experience slightly more weight loss during the first week due to water weight, but your weight loss will most likely stabilize to 1 to 2 pounds weekly.

Losing weight is only half the battle. The real challenge is keeping it off for good.

According to a 2023 review, people usually lose weight for 6 to 9 months before reaching a plateau, which is when weight loss drastically reduces or comes to a halt. At this point, many people gradually regain the weight they lost.

The authors note that around 15% of people maintain weight loss that is 10% greater than their starting weight.

Although maintaining weight loss is challenging, it’s likely to be much more difficult if you’re in a very low calorie deficit and lose a lot of weight very quickly. Severe calorie restrictions cause greater metabolic and hormonal fluctuations that can lead to extreme fatigue and hunger, eventually causing you to eat more food.

That’s why experts often suggest losing weight slowly but steadily. Most studies show that people who lose weight slowly but steadily are more likely to keep it off long-term.

What’s more, research found that gradual weight loss causes more decreases in fat mass and improvements in body composition and resting metabolic heart rate, which can help you maintain long-term weight loss.

Also, plans that encourage slow weight loss usually help you build lifestyle habits that can support sustainable weight management, such as:

  • exercising regularly
  • eating a balanced diet
  • managing stress levels
  • getting enough high quality sleep

For long-term weight loss, consider adopting a slower and more gradual approach.

While it’s tempting to try and lose weight fast, it’s usually not recommended.

Diets that promote rapid weight loss are often very low in calories and nutrients. This may put you at risk of several health problems, especially if you follow a rapid weight loss diet for many weeks.

Some complications from rapid weight loss may include:

  • extreme fatigue
  • loss of muscle mass and bone density
  • slower metabolism, which means you burn fewer calories daily
  • nutritional deficiencies, such as protein, fat, electrolytes, iron, vitamin B12, copper, and calcium
  • hormonal imbalances, such as insulin, testosterone, and thyroid hormones
  • mental health conditions, such as anxiety, stress, depression, and binge eating disorder
  • formation of gallstones, which are hardened pieces of material that form inside the gallbladder

You may also experience changes in your mood and energy levels, including dizziness, lethargy, irritability, and hunger.

Although slow weight loss might seem less appealing than quick weight loss, there are many things you can do to help speed up the process safely.

Here are a few tips to help you lose weight at a healthy rate.

  • Eat more protein: A high protein diet can help boost your metabolism, keep you fuller for longer, and preserve your muscle mass. Aim to eat 0.8 to 1.2 g per pound of body weight each day.
  • Limit sugar and starches: Research suggests that low carb diets may be effective for weight loss. Cutting back on sugar and starches can help keep you feeling full and energized.
  • Eat slowly: Chewing your food thoroughly might help you lose weight by making you feel fuller for longer and eat less food.
  • Get plenty of rest: A lack of sleep may boost your levels of ghrelin, the hunger hormone, and lower your levels of leptin, the fullness hormone. Not getting enough high quality sleep may leave you hungry, making it harder to lose weight.
  • Try resistance training: Resistance training or strength training is an important factor in supporting weight loss and developing lean muscle mass. It can also help boost your metabolism.
  • Try a high intensity workout: High-intensity interval training (HIIT) involves short, intense bursts of exercise. It can help improve body composition and increase fat burning, as HIIT continues to burn calories long after you work out.
  • Eat soluble fiber: Soluble fiber is a type of fiber that is digested in the intestine and may help support weight loss.

Consider setting a weekly weight loss goal of 1 to 2 pounds (0.45 to 0.9 kg) to prepare yourself for safe, effective, and sustainable weight loss.

Slow, steady weight loss may be easier to maintain long-term because it helps you develop more manageable habits, such as eating a balanced diet and exercising.

Losing weight too fast may increase your risk of side effects, including muscle loss, lower metabolism, and nutrient deficiencies.

Consider speaking with a healthcare professional if you’re unsure where to begin on your weight loss journey. They can help develop a weight loss program for you.