How to Lose Weight In a Week Fast and Safely, According to a Dietitian

If you have a special event coming up and you need to lose a lot of weight quickly, you may find yourself asking, how much weight can I lose in a week?

It is important to keep in mind that significant weight loss in a week is difficult and can be challenging to keep off.

Rapid weight loss of 5-10 pounds in a week may sound like a good idea, but it may lead to depriving your body of key nutrients causing you to feel fatigued, moody, and left with uncontrollable cravings.

Whatever your weight loss goals may be, it is possible to lose weight in a week and keep it off long term if you incorporate regular physical activity and change your eating habits.

In this article, we will discuss how you can lose weight in 7 days, achieve long-term weight loss, and be on your way to better health.

Here’s How to Lose Weight In 7 Days, According to Science

1. Eat Fewer Calories

Being in a calorie deficit by consuming fewer calories than your body needs is the key to weight loss.

Find out how many calories your body uses in a day, and cut back.

You can do this by using an online calculator, weight loss app, or schedule a visit with your nutritionist or Registered Dietitian, also referred to as RD.

Generally speaking, if you consume 3,500 calories over what your body burns in a week, you will gain a pound.

The same goes for losing a pound— if you cut 3,500 calories in a week, or about 500 calories per day, you will lose 1 pound or 1 kilogram per week.

If you create a calorie deficit of 7,000 calories per week by cutting calories and increasing physical activity, you will likely lose around 2 pounds or 1 kilogram per week.

According to the centers for disease control, or CDC for short, a safe rate of weight loss is 1-2 pounds or .5-1 kilogram per week (1)

Of course, these numbers are for the average adult and some may lose weight faster than others.

Some people may experience more difficulty losing weight than others due to lower metabolism or thyroid issues.

The gold standard to determine the number of calories your body uses per day and test your metabolism is metabolic testing by using direct or indirect calorimetry.

Metabolic testing is important because you may be the same age with similar anthropometric measurements as your friend, yet have a different metabolism due to different body compositions including fat and muscle mass.

Metabolic testing determines your resting metabolic rate or RMR.

You may see RMR used interchangeably with BMR, but they are slightly different.

Basal metabolic rate is the minimum calories your body needs to function compared to resting metabolic rate which is typically higher and a better overall picture of how many calories your body burns in a day.

Direct calorimetry is typically very expensive and consists of sitting inside of a chamber and measuring body heat to determine how many calories you burn.

Indirect calorimetry is more common and cost-effective.

It usually involves breathing into a mask for some time and determines RMR by measuring how much oxygen you take in versus the amount you breathe out.

By having a better idea of your calorie needs, you can properly adjust your diet and exercise routine to achieve your weight loss goals.

2. Make a Healthy Weight Loss Plan

If you are serious about losing weight within a week, it is very important to have a plan that includes a daily routine and stick with it.

This is especially true if you maintain a busy lifestyle.

Once you figure out how many calories your body needs to safely lose a modest amount of weight, it is time to create your weight loss plan.

Having a one-week diet plan ahead of time is one of the best ways to stay on track.

Divide your daily calorie needs by the number of meals and snacks you wish to have in a day.

For example, some people choose to have five small meals a day and others would rather have three larger meals during the day.

Decide on your meal plan for the week including breakfast, lunch, dinner, and snacks if you choose.

You may consider searching the internet for recipes that fit within your allotted calorie range per meal and creating a grocery list the week before.

Some people find success when meal prepping all or most of their items on Sunday before the week starts.

Even with a meal plan, it is important to also keep a food journal to keep track of what we eat.

It is ok to slightly veer off from your weight loss plan, and as long as you keep track of the food you eat throughout the day in your food journal.

Having everything documented in your food journal will allow you to reduce calorie intake from other snacks or meals during the day to stay within your calorie range.

Remember, no one is perfect and even if you feel defeated and completely fell off for a day or two, it is normal.

3. Eat Whole Foods

When aiming for a calorie deficit, it is important to eat quality foods.

Whole foods not only contain nutrients essential for your body and provide many health benefits, but they also help you feel full and promote satiety.

A healthy diet consists of carbs, lean protein, vitamins, minerals, healthy fats, and water.

The majority of your carbs should be from whole grains.

Whole grains are needed for energy and contain fiber which helps you feel fuller longer.

When choosing carbs, select brown rice, oats, and whole wheat bread.

Though white bread and white rice may have similar content when it comes to calories, whole grains have far more vitamins, minerals, and fiber.

Protein intake should consist of lean meat from fish, skinless chicken breast, and skinless turkey breast.

Plant-based proteins such as legumes, tofu, and beans are also good sources of lean protein and are a great option for vegan diets.

When consumed, protein has a thermic effect, meaning when you consume protein your body burns extra calories to digest it (2).

To get enough vitamins and minerals you should consume no less than 5, but aim for 10 servings of fruits and veggies daily.

To lose weight select lower-calorie fruits such as berries, apples, and grapefruit.

For veggies, focus on non-starchy vegetables because they are lower in carbohydrates and calories, but provide key nutrients and fiber.

Non-starchy veggies include broccoli, asparagus, green beans, and leafy greens.

You want to limit starchy vegetables like corn, peas, and potatoes because they are higher in calories and carbohydrates and can lead to weight gain if not consumed in moderation.

Healthy fats such as fatty fish, avocado, and nuts are essential to a whole foods diet.

Avocados are packed with fiber and healthy fats. While they are very healthy, you still want to be mindful of your intake.

One large avocado has a calorie count of around 300.

Diets rich in whole foods not only promote satiety, lower blood pressure, and reduce heart disease they also allow for more food intake throughout the day due to consisting of lower calories than heavily processed food.

For those with thyroid problems, a whole food approach combined with a low-calorie diet is often associated with successful weight loss.

4. Exercise Daily

A daily workout is a key component of your weight-loss plan if you are looking to lose a lot of weight within a week.

For example, if you cut 500 calories from your calorie intake and work out to burn off another 500, an average person would technically lose around 2 pounds weekly without overly restricting calorie intake.

Physical activity may also improve your mental health and make it easier to reduce cravings.

One study found that exercise improves overall mental health by reducing stress and anxiety (3).

Even brisk walking for 30 minutes most days of the week counts as exercise and can lead to a healthier lifestyle and reduction of body fat.

While a lot of women, in particular, have been hesitant about strength training because of fear of increased muscle mass, strength training may help you reach your goal weight faster because muscle burns additional calories at rest and promotes fat loss (4).

5. Avoid Junk Food

Junk food is very unhealthy and just as the name implies, it is junk.

Sweet and salty treats may taste great, but most junk food is made up of empty calories with little to no nutritional value.

By avoiding junk food, you can easily cut hundreds of calories per day.

The major junk foods you want to avoid are chips, cookies, candy, french fries, and other fried foods.

Avoid these 5 unhealthy foods at all costs!

6. Cut Out Soda

Soda and sugary beverages in particular not only cause spikes in blood sugar for those with diabetes but they can also quickly add empty calories to your diet and prevent weight loss.

For example, a 20-ounce soda contains around 240 calories.

This would require nearly 25 minutes of jogging to burn off.

Instead of reaching for a soda or other sugary beverages, consider drinking water or an all-natural zero-calorie drink instead.

According to one meta-analysis, both sugar and artificially sweetened beverages are linked to obesity (5).

Next time you find yourself reaching for a soda, grab water instead—your body will thank you.

7. Try HIIT Interval Training

HIIT or high-intensity interval training is a form of physical activity that has been studied to help with fat loss (6).

It is also very time efficient and can be completed in as little as 15-20 minutes.

A typical HIIT workout consists of short durations of intense exercise, followed by a recovery period.

For example, you may sprint for 30 seconds and rest for 30 seconds. Repeat for the duration of the exercise.

Studies have shown that the after burn or rate that calories are burned after a session of HIIT training may be higher than other forms of physical activity such as strength training or jogging (7).

8. Snack On Healthy Foods

While snacking on processed foods throughout the day may sabotage your weight-loss plan, high-quality snacks may lead to a decrease in appetite during meal times and reduce the likelihood of binges or excessive calorie intake at mealtime.

Typical snack foods are not only high in calories, they usually are high in sodium which can cause water retention, water weight gain, and bloating.

High protein snacks promote satiety and may help regulate appetite.

Some good examples of healthy snacks include lean protein sources like Greek yogurt, tuna, legumes, hard-boiled eggs, or almonds.

9. Eat An Early Dinner

Although weight loss is essentially calories in versus calories burned, the timing of our meals plays a part in the weight loss journey.

According to one study, participants who consumed a late dinner resulted in higher glucose levels and reduced fat burn when compared to those who consumed an earlier dinner (8).

In contrast, eating an early dinner has shown promising results for weight loss.

According to a newer study, those who followed a time-restricted eating pattern such as eating an early dinner promotes weight loss by suppressing appetite and increasing the amount of fat burned (9).

10. Skip Pastries After Dinner

If you enjoy an after-dinner piece of cake or pastry after dinner, saying no to after-dinner treats can help you achieve your weight loss goals.

Not only do sugary desserts have little to no health benefits, but they are also high in calories.

By skipping the after-dinner sweets, you can easily cut anywhere from 300-500 calories from your daily intake.

If you do choose to include an after-dinner dessert, make sure to account for it in your meal plan to ensure you stay on track with your weight loss goals.

11. Get Enough Sleep

Getting enough sleep is just as important as eating healthy and should be included in your weight loss plan.

The majority of adults do not get proper sleep at night.

One meta-analysis showed an increased risk of obesity in both children and adults that do not get enough sleep during the night (10).

According to the National Sleep Foundation, adults should get 7-9 hours of sleep nightly (11).

Without proper sleep, you may find it difficult to have enough energy to work out or resist the urge to skip high-calorie, processed foods and adhere to your meal plan.

12. Try Intermittent Fasting 

A newer trend in health and fitness is intermittent fasting also known as IF.

Intermittent fasting is eating freely during certain days or hours of the day and fasting during the other hours or days.

Some of the most common IF methods are:

16/8: This involves fasting for 14-16 hours and eating freely during the other 8 hours.

Eat stop eat: In this method, you fast for 24 hours and eat normally the next day. You fast 1-2 days per week.

5:2: This method involves following your normal diet pattern 5 days a week and restricting to less than 600 calories on the other two days.

During periods of fasting, you are allowed black coffee, unsweetened tea, and other zero-calorie beverages.

13. Avoid Fad Diets

Fad diets are very difficult to maintain and keep weight off.

One diet, in particular, the military diet, claims to help the average person shed up to 10 pounds or 4.5 kilograms in just one week.

The military diet consists of two phases and involves a 3-day meal plan and then a period of 4 days off.

Proponents of the diet claim that it was created by nutritionists in the military to help soldiers get into peak physical condition quickly and achieve a significant amount of weight loss.

This, however, is not currently used by any military institution.

During the 3-day meal plan on the military diet, one must follow a very low-calorie diet ranging from 1,100 to 1,400 calories per day and are only allowed three meals daily with no snacks.

During the other four days on the military diet, also known as phase two, you are allowed to eat a regular diet, but low-calorie foods are encouraged.

You repeat this cycle until goal weight is achieved.

Another fad diet that has been around for a while is a very low-carb diet consisting of cutting carbs to less than 50 grams per day.

Proponents of the diet claim that you will drop weight fast, but a lot of it is likely water weight.

While low carb diets (less than 150 grams) have been studied to be beneficial for weight loss, following an extremely low carb diet may be difficult to maintain and can deprive your body of nutrients it needs including fiber which can result in gut dysfunction.

These types of fad diets will likely be difficult to maintain and will not result in permanent changes due to their difficulty to stick to.

Proponents of the diets claim to drop unrealistic amounts of weight and if it seems too good to be true, it likely is.

Losing too much weight fast is never good for your health and can result in multiple nutrient deficiencies.

If you ever find yourself questioning a fad diet, it is best to speak with a Registered Dietitian to find out the facts and ensure you properly nourish your body.

Final Take

While it is possible to achieve weight loss in a week and keep it off long term, you likely will not see rapid weight loss or a weight loss of over ten pounds unless it is water weight.

You must make permanent changes.

To start, you must set your goal weight and determine a realistic goal for modest weight loss of 1-2 pounds per week.

By incorporating the above lifestyle changes and including regular physical activity in your weight-loss plan, monitoring your daily calorie intake, and eating healthy foods, you will be on the road to achieving your body weight goals in no time.

References

1. “Losing Weight.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 17 Aug. 2020, www.cdc.gov/healthyweight/losing_weight/index.html.
2. Westerterp, Klaas R. “Diet induced thermogenesis.” Nutrition & metabolism vol. 1,18 Aug. 2004, doi:10.1186/1743-7075-1-5
3. Kathleen Mikkelsen, Lily Stojanovska, Momir Polenakovic, Marijan Bosevski, Vasso Apostolopoulos,
4. Exercise and mental health,Maturitas,Volume 106,2017,Pages 48-56,ISSN 0378-5122, https://doi.org/10.1016/j.maturitas.2017.09.003.
5. Osterberg, K L, and C L Melby. “Effect of acute resistance exercise on postexercise oxygen consumption and resting metabolic rate in young women.” International journal of sport nutrition and exercise metabolism vol. 10,1 (2000): 71-81. doi:10.1123/ijsnem.10.1.71
6. D. Ruanpeng, C. Thongprayoon, W. Cheungpasitporn, T. Harindhanavudhi, Sugar and artificially sweetened beverages linked to obesity: a systematic review and meta-analysis, QJM: An International Journal of Medicine, Volume 110, Issue 8, August 2017, Pages 513–520, https://doi.org/10.1093/qjmed/hcx068)
7. Boutcher, Stephen H. “High-intensity intermittent exercise and fat loss.” Journal of obesity vol. 2011 (2011): 868305. doi:10.1155/2011/868305
8. Wingfield, Hailee L et al. “The acute effect of exercise modality and nutrition manipulations on post-exercise resting energy expenditure and respiratory exchange ratio in women: a randomized trial.” Sports medicine – open vol. 1,1 (2015): 11. doi:10.1186/s40798-015-0010-3
9. Chenjuan Gu, Nga Brereton, Amy Schweitzer, Matthew Cotter, Daisy Duan, Elisabet Børsheim, Robert R Wolfe, Luu V Pham, Vsevolod Y Polotsky, Jonathan C Jun, Metabolic Effects of Late Dinner in Healthy Volunteers—A Randomized Crossover Clinical Trial, The Journal of Clinical Endocrinology & Metabolism, Volume 105, Issue 8, August 2020, Pages 2789–2802, https://doi.org/10.1210/clinem/dgaa354
10. Ravussin, E., Beyl, R.A., Poggiogalle, E., Hsia, D.S. and Peterson, C.M. (2019), Early Time-Restricted Feeding Reduces Appetite and Increases Fat Oxidation But Does Not Affect Energy Expenditure in Humans. Obesity, 27: 1244-1254. https://doi.org/10.1002/oby.22518
11. Cappuccio, Francesco P et al. “Meta-analysis of short sleep duration and obesity in children and adults.” Sleep vol. 31,5 (2008): 619-26. doi:10.1093/sleep/31.5.619
12. Hirshkowitz, Max et al. “National Sleep Foundation’s sleep time duration recommendations: methodology and results summary.” Sleep health vol. 1,1 (2015): 40-43. doi:10.1016/j.sleh.2014.12.010

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