How Much Fat Can You Lose in a Week? (1% Rule vs 1-2 Pounds)

Weight Loss & Diets | Written by Nathan Petitpas | Updated on 19 June 2024

The comparison image displays a man's body before and after one week of weight loss, illustrating a noticeable reduction in body fat and improved muscle definition, prompting questions about the achievable fat loss within a week.

You can lose fat in a week through proper measures, and even without exercising, fat loss is still achievable.8

The exact amount is debated but most will say 1-2 pounds per week although 1% of your bodyweight per week, or the 1% rule is more accurate.

Remember, this is the max rate and it’s usually better to lose weight slowly since rapid weight loss poses risks, and you’re more likely to gain back the weight.

For this reason, we’ll cover ways to lose weight without exceeding the safe maximum rate, ways to keep the weight off, and the amount of weight you can lose without exercising.

How Much Fat Can You Shed in a Week? Is It Better to Lose 1% Body Fat vs 1-2 Pounds per Week?

How much body fat can you lose in a week is largely dependent on one’s starting weight. When focusing on weight loss, many aim to maximize weekly fat loss to achieve their goal weight sooner, often pondering on ways to get skinny fast or, more urgently, ways to lose belly fat overnight.1

However, this might not be the best goal, as people with gradual and steady weight loss (about 1 to 2 pounds per week) are more likely to keep the weight off.

Whether rapid weight loss or slow weight loss is more effective on body composition and metabolic risk factors has been studied intensively and it has been shown that weight loss at any rate can improve body composition, but that following a slower weight loss process is more favorable.2

While the 1-2 lbs per week rule is commonly advised, we alternatively recommend trying to lose 1% total body weight per week as this is a much more universal standard and better accounts for all starting weights. For example, the 1-2 pounds per week rule is not equally relevant or suitable to someone who is 150 pounds versus someone who is 350 pounds.

The 1% can be more equitably applied across the board and to all weights, as well as making the rate more attainable across genders, ages, mobility levels and other factors.

Note that no matter one’s starting weight, the first week will likely show the most rapid weight loss–especially for those on keto–but be mindful that this drastic weight loss is not (entirely) fat and is mainly water weight due to suddenly cutting carbs, burning glycogen, and more frequent urination as the body releases much of its water stores.

Tracking weight loss trends over time will give the most accurate view of true weight loss, so don’t be too concerned with day to day fluctuations.

How Much Fat Can You Shed in a Week Without Exercise?

We’ve discussed the amount of fat you can lose in a week through exercise, but achieving the same weight loss without exercise requires maintaining a very drastic calorie deficit.

As aforementioned, it is entirely possible to lose 3 lbs per week or more of water weight (or with a 1000 calorie daily deficit), but this should only be used as a short term strategy as it can be very unhealthy and unsustainable in the long run.

Long story short, you can lose the same amount of weight in a week without exercise (1% of your weight) but you’d have to eat much much less.

Factors That Determine How Much Weight Can Be Lost In a Week

There’s countless factors that influence the rate of weight loss but here’s an overview:

  • Starting weight
  • Amount of lean body mass
  • Activity levels
  • TDEE or total daily energy expenditure
  • Age
  • Gender
  • Height
  • Caloric intake

Furthermore, things like gastrointestinal (stomach) contents, sodium intake and levels of hydration can affect day-to-day weight so remember that if your weight fluctuates some from day-to-day it’s usually nothing to worry about.

How To Shed Weight in a Week (And Keep It Off)

While it is completely possible and often desirable to lose body fat in a week, remember that much of that weight in the first week will actually be water. A better goal is to aim for permanent weight loss that is cut slowly yet consistently over time.

The following are some ideas for losing weight in a week, but that can also be implemented into healthy long term weight loss routines.

Diet

The rate at which you can lose fat in a week depends significantly on the effectiveness of your adherence to various weight loss diets. Whether following the keto diet, maintaining a caloric deficit, or intuitive eating for weight loss, here are some tips that can boost weight loss in just a week.

  • Avoid alcohol, sugary juices, and sodas
  • Cut out refined carbs as well as refined and added sugars
  • Drink plenty of water
  • Eat fiber and protein rich foods
  • Follow proper serving sizes and portions
  • Maintain a caloric deficit
  • Read nutrition labels

Exercise

The other major factor in the amount of fat loss per week is possible, aside from one’s diet, is how active they are and how many calories are burned through physical exercise. Thankfully this can take nearly countless forms so there are tons of opportunities to find what you enjoy and switch it up consistently to always keep working out fun.

A pair of women's feet wearing blue shoes and gray leggings, walking up the stairs outdoors.

Source: happyveganfit from Pixabay6

  • Build more muscle
  • Go for a walk on your lunch break
  • Incorporate cardio into your daily routine
  • Integrate strength training weekly
  • Join a HIIT workout
  • Practice resistance training
  • Sign up for a spin class
  • Try something new (swimming, yoga, rock wall climbing)

Lifestyle

Although diet and exercise are always given the most air time, creating an overall healthy lifestyle with beneficial routines and habits is vastly underrated. Let’s jump into several options for dropping body fat in a week and see how a balanced and healthy lifestyle can aid in weight loss.

  • Ask a friend or family member to help support you and be an accountability partner
  • Avoid using or looking at blue light before bed
  • Enjoy a refreshing walk in nature
  • Get sufficient sleep on a regular schedule
  • Make time for yourself
  • Pick up a new hobby (disc golf, rowing, geo-caching)
  • Practice meditation and mindfulness

What Is a Safe Rate of Weight Loss?

Losing one pound of fat necessitates burning approximately 3500 calories, so maintaining a daily 1000 calorie deficit could result in shedding around 2 pounds each week.

But anything beyond that is extremely dangerous and could prompt the body to slow down it’s metabolism to extreme levels, and the weight loss being sought will actually be less likely to occur as the body tries to preserve fat.

As we briefly touched on above, a safe and advisable rate in regards to the amount of fat that can be lost in a week is to shoot for 1% of one’s total body weight being cut each week. Eating regular nutritious meals and staying hydrated and active are the most safe, healthy, and effective ways to lose weight over time.

Risks of Rapid or Extreme Weight Loss

As mentioned previously, some risks of rapid or extreme weight loss include dangerous health risks including the body shutting down. While various trendy or popular diets promote rapid weight loss within days or weeks, these are often gimmicks that do not prioritize anyone’s best interests or health.

A guideline for a medically safe rate of weight loss for the treatment of obesity, based on risk of gallstone formation suggests that weight loss should not exceed an average of 1.5 kg or about 3 lbs per week, as the risk of gallstones forming increased drastically during active weight loss the faster it was being lost.3

Other major health risks associated with accelerated weight loss may include:

  • Blood Pressure Issues
  • Brain Fog
  • Brittle Nails
  • Confusion
  • Constipation
  • Dehydration
  • Depression
  • Dizziness
  • Fatigue
  • Greater Amounts of Loose Skin
  • Hair Loss
  • Headaches
  • Heart Irregularities
  • Irritability
  • Joint Pain
  • Menstrual Irregularity
  • Muscle Loss
  • Organ Damage

Is There a Noticeable Difference Before and After 1 Pound of Fat Loss?

Whether or not there is a noticeable difference before and after 1 pound of fat loss largely depends on one’s starting weight but that 1 lb very likely will not make a huge difference in how one feels; however, just 1 lb can relieve some pressure on the back and knees and is better for the body overall even if not fully felt the effects of yet.

However, one pound of weight loss is still one pound closer to goal weight so even if it feels small, a great amount of fat loss consists of many small 1 lb losses.

Woman's midsection with visible belly fat, and her hand pinching the skin on the side of her waist.

Source: Bru-nO from Pixabay7

Since water weight and gastrointestinal contents can fluctuate constantly depending on the amount of fiber, sodium, and carbs consumed–and scales can be off by up to 5%–it is wise and more accurate to track one’s trending weight or the average weight week over week rather than getting caught up in daily variations or gaining/losing a pound here and there.

The app MacroFactor has this weight trend-tracking feature and can be a useful tool.5

Potential Causes of Unexplained Weight Loss

Potential causes of unexplained weight loss could be minor or short term, but other causes may be much more concerning and pose immense health issues. Any drastic unexplained weight changes should be reported to your doctor immediately to ensure that there isn’t a more dire underlying problem.4

Although there are far more potential causes of unexplained weight loss, some prominent ones include:

Cushing’s Syndrome: A hormonal disorder caused by long term exposure to high levels of cortisol (naturally from one’s adrenal gland or from taking oral corticosteroid medication). Cushing’s Syndrome can be indicated by a fatty hump between one’s shoulders, pink or purple colored stretch marks, high blood pressure, bone loss, a rounded face, and even type 2 diabetes.

Cushing’s Syndrome often causes progressive weight gain in the trunk, face, and neck areas but can also have the opposite effect and cause sudden unexplained weight loss.

While treatments are available and symptoms can be improved especially if caught early, this is a perfect example of why it is important to see a doctor about unexplained weight gain (or loss).

Depression: Depression is a common culprit of drastic weight fluctuations as one may become withdrawn and uninterested in things they used to enjoy, even including eating. Depression can also dampen the senses and feelings, causing one to enjoy eating less and neglect their basic needs including hygiene, mental health, and nutrition.

Medications: Certain medications in every category and for nearly every purpose have a side effect of potential weight loss, so if you have noticed a drastic fluctuation in your weight after starting a new prescription, check the label or speak with your doctor to ensure that taking it is safe and right for you.

Hyperthyroidism: This is the term for when the thyroid gland produces too much of the thyroid hormone, often referred to as an “overactive thyroid.” An overactive thyroid increases the body’s metabolism, which can lead to hand tremors, muscle weakness, irregular heartbeat, nervousness, and weight loss.

The amount of fat you can lose in a week depends heavily on one’s starting weight and activity level, but a great rule to go by is following 1% total body weight lost per week.

Frequently Asked Questions

How Much Fat Can You Lose in a Day?

How much fat can you lose in a day is quite minimal. The number on the scale could vary from 1-5 pounds given many variables including gastrointestinal contents, fluid retention, sodium and glycogen levels, timing of meals, and much more, but true fat loss takes time.

How Much Fat Can You Lose in 2 Weeks?

How much fat can you lose in 2 weeks would safely be 4-5 pounds at the most. While more than this is possible and has been done, it is not advised and would primarily be water weight lost.

What Is the Most Weight You Can Lose in a Week?

The answer to what is the most weight you can lose in a week or max weight loss per week in extreme cases could be higher, but it is very dangerous to exceed about 2 lbs or 1kg a week of weight loss; even that is pushing it for a rate of long term or sustainable weight loss.

Is Rapid Weight Loss Sustainable?

Although body fat loss per week could be higher than 1% of one’s total body weight per week and rapid weight loss is entirely possible in the short term, it’s not sustainable nor advised as it can bring a multitude of health risks including hair loss, organ damage, heart issues, menstrual irregularities, and more.


References

1Centers for Disease Control and Prevention. (2022, September 19). Losing Weight. CDC. Retrieved February 21, 2023, from <https://www.cdc.gov/healthyweight/losing_weight/index.html>

2Ashtary-Larky, D., Ghanavati, M., Lamuchi-Deli, N., Payami, S., Alavi-Rad, S., Boustaninejad, M., Abbasnezhad, A., & Alipour, M. (2017, July). Rapid Weight Loss vs. Slow Weight Loss: Which is More Effective on Body Composition and Metabolic Risk Factors? National Library of Medicine. Retrieved February 21, 2023, from <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5702468/>

3Weinsier, R., Wilson, L., & Lee, J. (1995, February). Medically safe rate of weight loss for the treatment of obesity: a guideline based on risk of gallstone formation. National Library of Medicine. Retrieved February 21, 2023, from Medically safe rate of weight loss for the treatment of obesity: a guideline based on risk of gallstone formation <https://pubmed.ncbi.nlm.nih.gov/7847427/>

4Rush. (2023). Unexplained Weight Changes. Rush.edu. Retrieved 21 February, 2023, from <https://www.rush.edu/news/unexplained-weight-changes>

5MacroFactor. (2023). Weight Trend. MacroFactor. Retrieved February 24, 2023, from <https://help.macrofactorapp.com/dashboard/weight_trend/>

6happyveganfit. “Free Image on Pixabay – Remove, Weight Loss, Slim, Diet.” Pixabay, 19 October 2019, Accessed 6 April 2023. <https://pixabay.com/photos/remove-weight-loss-slim-diet-4559331/>

7Bru-nO. “Pinch Thick Belly – Free photo on Pixabay.” Pixabay, 31 October 2019, Accessed 6 April 2023. <https://pixabay.com/photos/pinch-thick-belly-fat-overweight-4590161/>

8“14-Day Fat Loss Transformation (Minicut 2023).” YouTube, 22 January 2023. Accessed 15 April 2023. <https://www.youtube.com/watch?v=vaZ0JTTMjWE>

About the Author

Nathan Petitpas

Nathan has been a fitness enthusiast for the past 12 years and jumps between several types of training such as bodybuilding, powerlifting, cycling, gymnastics, and backcountry hiking. Due to the varying caloric needs of numerous sports, he has cycled between all types of diets and currently eats a whole food diet. In addition, Nathan lives with several injuries such as hip impingement, spondylolisthesis, and scoliosis, so he underwent self-rehabilitation and no longer lives with debilitating pain.