Why You Shouldn’t Focus on Losing Weight in Just 1 Week

You’ve probably heard friends and loved ones declaring that they “want to lose a few pounds” for a special event like a wedding, holiday, or vacation.

In the attempt to quickly lose weight, many people turn to fad diets, juice cleanses, very low calorie “detox” programs, and more.

While it’s possible to lose a substantial amount of weight in a week or two, it isn’t a healthy goal or something you should attempt.

For example, if you’ve ever had the stomach flu or another illness that causes diarrhea, vomiting, or a lack of appetite, you probably lost a noticeable amount of weight in a short time. This would have been due to fluid loss and eating too few calories (1).

Likewise, if you severely restrict calories and overexercise, you’ll lose weight quickly — even in a week.

However, it isn’t healthy, sustainable, or safe. Plus, while these practices may lead to short-term weight loss, you’ll likely gain any lost weight back quickly once you go back to your old habits (2).

Even though many weight loss companies, influencers, and dieting books suggest otherwise, there is no “magic bullet” when it comes to weight loss.

Instead, your focus should be on safe, sustainable methods that promote weight loss over a much longer period.

By playing the long game and opting for dietary and lifestyle modifications based on your specific needs, goals, preferences, and lifestyle, you stand a much better chance of reaching and maintaining a healthy body weight.

Summary

Fast weight loss is possible, but trying to lose the most weight in the shortest time isn’t healthy. It’s also likely that you’ll regain the weight as soon as you return to your normal dietary and lifestyle practices.

There are many social, physical health, and mental health reasons why rapid weight loss can be problematic.

Built on unattainable beauty standards

Weight is a concern for many people.

A large review of 72 studies that included data on over 1 million participants from around the world found that between the years 2010 and 2015, about 40% of adults in the general population had tried to lose weight (3).

The review also found that weight loss attempts were more common among women — even those with a healthy weight. The researchers suggested that this could be due to cultural pressures to be thin and unattainable body and beauty standards (3).

You might regain the weight

While some people realize that weight loss takes time and opt for sustainable methods, others crave extreme, rapid results.

For example, people who wish to drop 10 pounds in just 1 week — perhaps to fit into a certain outfit for an event like a wedding or family reunion — may focus on the immediate future and how to lose the most weight in the shortest amount of time.

This could cause them to use unhealthy and unsustainable diets and cleanses, such as eating just a few hundred calories a day, taking unsafe dietary supplements, or engaging in extreme exercise coupled with a liquid diet.

While you’re likely to lose weight by following these methods, you might regain the lost weight soon after returning to your prior eating and exercise habits (2).

You may lose more muscle and water weight

Studies show that rapid weight loss is generally accompanied by more lost muscle and water weight compared with slower weight loss methods.

In a small study in 42 people with overweight or obesity, one group lost 5% of their body weight over 5 weeks through a daily 1,000–1,500 calorie deficit, while another group lost 5% of their body weight over 15 weeks with a 500–750 calorie deficit (4).

At the end of the study, the people in the rapid weight loss group lost less body fat, more muscle mass, and more water weight compared with the slow weight loss group (4).

Can affect your resting energy expenditure

Losing weight too quickly may also affect your resting metabolic rate (RMR), which reflects how many calories you burn at rest.

In the previously mentioned study, those in the rapid weight loss group experienced greater reductions in their RMR compared with those in the slow weight loss group (4).

To be clear, any weight loss method that reduces your calorie intake will likely also lower your RMR.

Still, you can minimize negative metabolic adaptions from calorie restriction, such as muscle loss, a decreased RMR, and increased hunger, by opting for a less restrictive diet, a smaller daily calorie deficit, and an overall slower weight loss strategy (5, 6).

Might land you in a loop of yo-yo dieting

Because you’ll likely regain any weight you’ve lost through restrictive dieting methods, you may be tempted to try another crash diet later on.

This can lead to a pattern of weight loss and regain called “yo-yo dieting” or weight cycling. This not only takes a physical toll on your body but also potentially your mental health (7).

While it’s completely understandable why you might want to lose excess body fat quickly, it’s best to create a plan that promotes weight loss over the long term. This is especially true if you have a significant amount of weight to lose.

Summary

Extreme, rapid weight loss methods, including crash diets and overexercising, aren’t the best choices for long-term weight loss or maintenance. They can lead to weight cycling, a loss of muscle mass, and more.

Instead of trying to lose the most weight in the shortest possible time, try using the following tips to create a long-term, sustainable, personalized, and healthy weight loss plan.

1. Understand your goals and ‘whys’

If you want to lose weight, you probably have a few reasons why.

Wanting to feel and look better for yourself or others is a common motivator behind weight loss. Yet, wanting to lose weight for reasons that aren’t related to appearance may increase your odds of success (8, 9).

Extrinsic motivation is when your primary motivators come from outside sources, such as wanting to look thin at a wedding or look a certain way to gain popularity on social media.

Intrinsic motivators come from within yourself. Examples include wanting to improve your self-esteem, mood, health, and energy levels (10).

Studies show that while people motivated by extrinsic factors can achieve short-term weight loss, those who are more motivated by intrinsic factors tend to be more successful when it comes to keeping weight off long term (9).

In fact, a study including 607 people found that participants whose main motivator was physical appearance maintained 3.5% less weight loss than those whose main motivator wasn’t associated with physical appearance (11).

The people who successfully maintained their weight loss were more likely to be motivated by health reasons (11).

While aiming to look better for yourself or others can be one of your motivators, focusing on nonappearance-related motivators, such as improved stamina and mood or reduced triglyceride and blood pressure levels, may up your odds of successful long-term weight loss.

2. Be realistic

If you’ve decided to lose weight, it’s important to choose realistic, attainable goals.

Aim for slow, steady weight loss rather than setting unrealistic goals like losing 5 or 10 pounds in 1 week.

What exactly “slow and steady” looks like for you can depend on how much weight you want to lose combined with your overall health and lifestyle preferences, among other factors.

Working with a healthcare professional like a registered dietitian can help you determine a safe and reasonable weight loss goal — and how to get there.

3. Avoid overly restrictive, fad, and very low calorie diets

Juice cleanses, 500-calorie-a-day plans, influencer “weight loss challenges,” liquid diets, and programs that rely on stimulants like caffeine pills are just a few examples of diets to avoid.

Even though programs that promise to help you lose 10 or more pounds in a week may be tempting, they’re not worth your time, energy, or money and can take a toll on your physical and mental health.

Weight loss is not about punishing yourself or suffering through a diet that you hate. A healthy, sustainable, weight-loss-promoting dietary pattern should be nourishing, enjoyable, and give you the energy you need to feel your best.

4. Participate in activities that you enjoy

Shifting your focus from weight loss to improved physical fitness may boost your overall health and reduce your disease risk.

One review found that increased physical activity or cardiorespiratory fitness was linked to lower mortality risk compared with intentional weight loss (12).

Plus, one study in 193 people found that physical activity improved heart-health markers and helped participants maintain their weight loss over time (13).

Rest assured, though, that this doesn’t mean you need to participate in daily, intense exercise.

Instead, simply being more active — such as regularly participating in activities that you enjoy like hiking, walking, biking, and swimming — can help you maintain weight loss over time and improve your overall health.

5. Choose small calorie reductions to induce slow, sustainable weight loss

Most crash diets and fast weight loss programs severely restrict calories. While this can certainly make the number on the scale go down quickly, it can also cause metabolic adaptations like increased hunger, loss of lean body mass, and decreased RMR (14).

Plus, significantly cutting calories can negatively affect your mood and energy, leaving you feeling miserable and demotivated.

To promote slow weight loss and minimize negative metabolic adaptations, choose small calorie deficits of about 200–300 calories per day rather than 1,000 calories or more (5, 6).

Your energy needs depend on many factors like your age, activity levels, and sex. A registered dietitian can help you determine your daily needs and what an appropriate calorie reduction may look like for you.

The National Institutes of Health also offers a free online tool to help you plan for long-term weight loss.

6. Get help from the right people

Weight loss — especially the sustainable, long-term kind — can be challenging and feel isolating.

Working with a registered dietitian and other healthcare professionals like a therapist may help you reach your health and wellness goals more easily. They can also advise you on safe, evidence-based ways to support your physical and mental health.

Be wary of anyone offering nutrition or mental health advice who doesn’t have the proper credentials, such as self-proclaimed social media “experts.”

Following a weight loss program from an unqualified person can be dangerous, especially if it involves extreme calorie restriction, weight loss supplements, liquid cleanses, or extreme exercise routines.

7. Be kind to yourself

Remember that you are so much more than your appearance. In fact, your weight and appearance are the least interesting things about you.

Your body deserves nourishment, kindness, and respect, no matter how you think you look or how much you currently weigh.

Losing excess weight can improve your overall health and self-esteem, but how you approach weight loss can affect physical and mental health.

Losing weight or improving health shouldn’t be painful or make you feel bad about yourself. If you’re currently following a program that does, ditch it now.

Instead, take the time to develop a plan that puts your future health first, prioritizing nourishing, nutrient-dense foods, enjoyable movement, stress reduction, getting enough sleep, and plenty of self-care.

Summary

Focusing on intrinsic motivators, setting healthy and realistic goals, working with qualified healthcare professionals, engaging in enjoyable physical activity, and being kind to yourself are ways to support overall health and sustainable weight loss.

Fast weight loss, such as losing 10 pounds in a week, is possible — but it’s usually not worth it. In fact, it could be detrimental to your physical and mental health.

In reality, plans and programs that promise rapid weight loss or extreme results are best avoided.

If you’re interested in losing weight, it’s best to focus on improving your overall health through a sustainable and nourishing dietary and activity plan that involves getting enough calories from nutritious foods and participating in consistent physical activity.