1000 Calorie Deficit: How Long to See Real Results (Full Timeline)

Weight Loss & Diets | Written by Nathan | Updated on 17 August 2022

A man is holding a fork that has a cucumber on it with his hand on his chin and lettuce, tomatoes and other veggies sitting below him on a table while wondering if a 1000 calorie deficit diet is worth it.

A 1000 calorie deficit is on the “extreme” end of dieting which makes you wonder if it’s too much, even practical, and how long to see real results? 

After all, extreme diets are often preached by Instagram influencers, keto experts, and just about any other weight loss guru so of course dieters may be weary of proceeding. But don’t worry, because we’ll break down every part of a 1000 calorie deficit diet such as if it’s safe, potential risks, how quick results can be seen and how to overcome plateaus despite being in a massive deficit. 

Is it Safe to be in a 1000 Calorie Deficit a Day?

Firstly, it’s important to remember that a 1k calorie deficit does not equal starvation. According to the FDA’s Dietary Guidelines for Americans, the average adult man should consume 2,400-3,200 calories each day and the average adult woman should consume 1,800-2,400 each day (depending on age and activity level).

Of course, the average American usually overshoots that number, consuming about 3,600 calories each day.1 Therefore, most people can safely be in a 1,000-calorie deficit as they try to lose weight.

Potential Risks of a 1000 Calorie Deficit

A 1,000 calorie deficit can result in quick weight loss (and all the compliments that come with it). These results can be very exciting and inspiring, but it’s important to remember that this diet is not without its risks. After all, the body gets accustomed to the nutrients it receives on a regular basis, and a dramatic decrease is bound to have some side effects.

Some of the common risks of a 1000 calorie deficit include dizziness, fatigue, headaches, and (obviously) hunger. Eating an extremely low-calorie diet for too long can also lead to issues like gallstones. This happens when the liver releases extra cholesterol into the bile stored in your gallbladder, which can later harden into stones and become very painful.

Is a 1000 Calorie Deficit Too Much of a Deficit?

Individuals who eat as much as the average American can safely be in a 1,000 calorie deficit — in fact, it’s probably to their benefit. But if a 1k calorie deficit is causing you to lose too much weight, eat too little, or don’t weigh very much, then cutting this many calories at once may be too much for you.

Remember, 1,200 calories are the minimum for any adult; if cutting 1,000 calories means eating 500 calories each day for a month, you might want to reconsider your diet plan! A safe and healthy diet means eating at least 1,200 calories each day, and it should only result in a 1% loss of body weight each week.2

It’s also important to remember that a 1,000-calorie deficit is not a healthy diet in the long term. Eating at this deficit can yield excellent results, but those losses diminish over time. For example, a 2013 study from the journal Obesity found that participants who cut 1,000 calories from their diet lost more weight than those who only cut 500 calories in the first six months of the study. After those six months, however, the 1,000-calorie group saw far fewer losses — and in fact, they were more susceptible to weight regain.

A smartphone that is taking a picture of various foods like pasta, corn and beans with icons showing how many calories is in each food item.

This study indicates two things: cutting 1,000 calories is generally not sustainable, but it does work in the short term. We advocate for cycling your diet between low-calorie weight loss and a calorie maintenance phase, or a period of time focused only on maintaining your current weight and eating enough calories to do so.

Hearing about the risks and caveats of a 1,000 calorie deficit might make you want to forget this diet plan — or even give up on weight loss altogether. DON’T! With the right diet cycle (weight loss coupled with a maintenance phase), anyone can safely and effectively shed all the pounds they want to lose.

How Much Weight Can I Lose With a 1000 Calorie Deficit?

The greatest thing about caloric deficits is that they work. There’s no limit to the number of pounds you can lose with a 1000 calorie deficit — but you will experience diminishing returns if you keep up that deficit for too long. This is because a low-calorie diet can slow metabolism, which works against your weight loss goals.

How Long Is it Okay to Be in a 1K Calorie Deficit?

While participants in the Obesity study did see results from their 1k calorie deficit for six months, the best way to see sustained weight loss results is to practice this deficit for six to eight weeks. After that period, it’s best to spend the same amount of time (or at least half the amount) trying to maintain those losses.

How Fast Will I Lose Weight if I’m in a 1000 Calorie Deficit?

In most cases, dieters will lose 1-2 pounds per week when they cut 1,000 calories from their daily intake.3 However, the safest way to lose weight is to limit losses to 1% of your body weight each week. Someone who is 200 lbs or more can safely use a 1,000 calorie deficit to lose two pounds a week, but someone who is 150 lbs should only lose 1.5 lbs (1% of their weight) each week.

Therefore, we’ll show you how to approximate how much you will lose in a 1000-calorie deficit through the simple use calculators or TDEE rough calculations.;

Personalizing the Calculation: How Long it Will Take YOU to See Results in a 1K Calorie Deficit

The first step to finding out how many calories will put you at a 1,000-calorie deficit is to determine your total daily energy expenditure (TDEE)–the number of calories you burn each day–but if you’re unsure about the numbers below, start with this Body Weight Planner that helps calculate how many calories you need a day in order to reach your goals.4

And if you want to find your TDEE using the Body Weight Planner above, simply set your goal to the same weight.

To discover your TDEE manually, start by calculating your basal metabolic rate (BMR) — the calories you burn by simply existing. The formula for BMR is:

  • For men: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5 (kcal / day)
  • For women: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) -161 (kcal / day)

Once you know your BMR, multiply that number based on your activity level:

  • Sedentary = 1.2
  • Lightly active = 1.375
  • Moderately active = 1.550
  • Very active = 1.725
  • Extra active = 1.9

The final total is your TDEE! If you want to be in a 1,000 calorie deficit, simply subtract 1,000 from that figure and use that number for your daily caloric intake.

To better understand how much weight someone can lose at a 1,000 calorie deficit, let’s look at an example. Imagine that someone with a TDEE of 2,000 wants to lose weight. If they operated in a 1,000 calorie deficit, their progress would be as follows:

  • Week 1: Consumed 7,000 calories, burned 7,000 calories, lost 2 lbs (3,500 calories = 1 lb of fat)
  • Week 2: Consumed 7,000 calories, burned 7,000 calories, lost 4 lbs total
  • Week 3: Consumed 7,000 calories, burned 7,000 calories, lost 6 lbs total
  • Week 4: Consumed 7,000 calories, burned 7,000 calories, lost 8 lbs total
  • Week 5: Consumed 7,000 calories, burned 7,000 calories, lost 10 lbs total
  • Week 6: Consumed 7,000 calories, burned 7,000 calories, lost 12 lbs total
  • Week 7: Consumed 7,000 calories, burned 7,000 calories, lost 14 lbs total
  • Week 8: Consumed 7,000 calories, burned 7,000 calories, lost 16 lbs total

After week 8, shift into a maintenance phase that lasts at least four weeks (but ideally eight). While it may be tempting to skip the maintenance phase, do not do so. Maintaining allows the metabolism to return to normal — which means you’ll see EVEN MORE RESULTS when you create that deficit again.5

Is it Possible to Build Muscle While in a 1000 Calorie Deficit?

In plain terms, no, it is generally impossible to build muscle in a deficit of 1000 calories since the body needs extra fuel to build muscle. The only exception to this is new lifters and even then, any muscle gain will be short-lived.

In fact, most experts recommend eating around 500 extra calories each day to see muscle gain.6 With a 1,000 calorie deficit, the body simply doesn’t have the proteins needed to help you bulk up!

This reality may be disappointing for folks who want to lose weight and build muscle. Luckily, it is possible to build muscle when using a 1000 calorie deficit: just hit the weights during the maintenance phase instead of the cutting phase. This period gives your brain the freedom to “take a break” from the diet and focus on other aspects of your health like lifting or improving flexibility. Just remember that a mental break from a diet doesn’t mean a “cheat day” — that’s how folks end up gaining 5 pounds in a week.

Will I Lose Muscle On a 1000 Calorie Deficit?

Obviously, no one wants to lose muscle when they’re trying to lose fat. Such a concern can put some people off calorie cutting… but don’t worry. As long as you are cutting calories responsibly — cycling between low-calorie and maintenance phases, and losing no more than 1% of your body weight each day — you shouldn’t have to worry about muscle loss.

But if you step over the 1% weight loss rule, you’re destined to lose some muscle.

I’m Eating a 1000 Calorie Deficit and Not Losing Weight…What Gives?

There’s nothing more frustrating than striving to lose weight and just… Not. Seeing. Results. Is it really possible to eat a 1,000-calorie deficit and still not lose weight?

A body weight scale with various junk food around it such as snickers, Hershey milk chocolate, onion rings, cookies chips, and kettle corn.

In the long-term, not really — but it might be that your sodium and fluid levels are thrown off from dieting too long or too hard. If so, try one of the following fixes:

  • Recalculate TDEE: Your caloric deficit won’t yield results if it’s calculated incorrectly. Use the right formula and be honest about your activity levels, so you can accurately decrease your daily caloric needs.
  • Try a maintenance phase: We’ve already mentioned that a low-calorie diet offers diminishing returns over time. No matter how much weight you want to lose (or how fast you want to lose it), you need occasional maintenance phases to help your body recover. If you’re noticing a plateau (especially at 8 weeks or more), it might be time to make the shift.
  • Move and lift regularly: The old saying goes that “abs are made in the kitchen,” and that’s true — diet plays a pivotal role in weight loss and fitness. However, it is also important to continue cardio and lifting throughout your weight loss journey, as this will help the body continually burn fat.
  • Get enough sleep: Just one or two nights of poor sleep can cause temporary water retention in the body — and that can put a real damper on your weight loss results.7 Additionally, studies show that improved sleep can help with weight loss.
  • Minimize stress: Like sleep, stress can also trigger water retention and interfere with weight loss. This is because stress releases a hormone called cortisol, which can increase sugar cravings and slow down metabolism.8
  • Fuel with food: If you’re eating 1,000 fewer calories each day, it’s vital that the calories you do eat give your body the nutrients you need to be your best. Instead of sugary, low-calorie foods, look for nutrient-rich foods that will actually fuel your body. Read the labels on EVERYTHING you eat! Even a simple choice like Shakeology vs. SlimFast can impact your weight loss results.
  • Don’t over (or under) lose: Trying to lose more than 1% or less than 0.5% of your body weight can interfere with your results. Losing too much can put the body into starvation mode (which leads to a slower metabolism and easier fat storage), while losing too little simply won’t deliver noticeable results.
  • Be consistent: Plateaus are a natural part of any weight loss journey. Sometimes, the best thing to do is stay consistent and be patient!

Tips to Curb Hunger On a 1000 Calorie Deficit Diet

Ok, you’re ready to decrease your daily calories by 1,000 — but you’re not ready to deal with that hunger. Here are a few tips to curb your appetite while in a deficit:

  • Eat more fiber: Foods like legumes, asparagus, oats, Brussels sprouts, and flax seeds contain viscous fibers — and viscous fibers can help reduce your appetite.9 Get plenty of these in your diet to help you stay fuller throughout the day.
  • Try fasting: Intermittent fasting is a great way to cut daily calories, and some research suggests that it could actually change the body’s hunger cues over time.10 Start with a plan that introduces fasting for beginners to ease you into this new way of eating.
  • Don’t drink your calories: Don’t spend valuable calories on sugary drinks, alcohol, fruit juices, or other drinks. These calories may be sweet at the moment, but they won’t keep you full!

Remember, weight loss is never easy — but it’s definitely worth it. If you keep a positive attitude (maybe with help from some weight loss affirmations), eat a 1000 calorie deficit (with maintenance phases), and consistently pursue your goals, you can look and feel like the best version of yourself.


References

1Gould, S. (2017, May 10). 6 charts that show how much more Americans eat than they used to. Business Insider. Retrieved July 25, 2022, from <https://www.businessinsider.com/daily-calories-americans-eat-increase-2016-07>

2Davis, PhD, M. (2021, January 18). Stop rushing your weight loss! Renaissance Periodization. Retrieved July 25, 2022, from <https://rpstrength.com/expert-advice/slow-losses>

3Mayo Clinic Staff. (2020, December 8). Counting calories: Get back to weight-loss basics. Mayo Clinic. Retrieved July 25, 2022, from <https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/calories/art-20048065>

4Bodybuilding. (n.d.). TDEE Calculator: Calculate Your Maintenance Calories. BodyBuilding. Retrieved July 25, 2022, from <https://www.bodybuilding.com/fun/calculate-your-total-daily-energy-expenditure-tdee.html>

5Baker, M. (2020, May 13). Maintenance Phases – What, Why, When, and How Long? Macabolic. Retrieved July 25, 2022, from <https://www.macabolic.com.au/blog/2020/5/13/maintenance-phases-why-why-when-amp-how-long>

6Bewley, M. (n.d.). Building Lean Muscle, Part 4: When, How, and How Much to Eat. Volt Athletics. Retrieved July 25, 2022, from <https://blog.voltathletics.com/home/2015/9/9/blm-part-4-when-how-and-how-much-to-eat>

7Fox, J. (2018, September 28). 9 Reasons the Scale Might Be Lying to You. Active. Retrieved July 25, 2022, from <https://www.active.com/fitness/articles/9-reasons-the-scale-might-be-lying-to-you>

8Scott, PhD, E. (2021, January 5). How Stress Can Cause Weight Gain. Very Well Mind. Retrieved July 25, 2022, from <https://www.verywellmind.com/how-stress-can-cause-weight-gain-3145088>

9Healthline. (n.d.). Fiber Can Help You Lose Weight — But Only a Specific Type. Healthline. Retrieved July 25, 2022, from <https://www.healthline.com/nutrition/fiber-can-help-you-lose-weight>

10Editor. (2017, October 20). Fasting may change the body’s hunger response – here’s what to do about it. Diabetes.co.uk. Retrieved July 25, 2022, from <https://www.diabetes.co.uk/in-depth/fasting-may-change-bodys-hunger-response-heres/>

About the Author

Nathan

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.