400 Calorie Deficit: Is It Healthy & How Much Can You Lose?

If you want to lose weight, you might wonder whether a 400-calorie deficit is healthy and if it will be enough to get you to your desired weight.

Is a 400 calories deficit healthy? Eating at a deficit of 400 calories is considered a healthy and sustainable deficit to get you to your weight loss goal.

If you’re consistent with a 400-calorie deficit, you can expect to lose around 0.5-1 lb per week. Creating a 400-calorie deficit can be as simple as reducing your portions at each main meal.

In this article, we will discuss:

  • What does a 400-calorie deficit mean?
  • Is a 400-calorie deficit healthy?
  • Should you use a 400-calorie deficit?
  • What can you expect from a 400-calorie deficit?
  • How to achieve a 400-calorie deficit
  • Is a 400-calorie deficit worth it? My practical advice

What Does a 400-Calorie Deficit Mean?

A 400-calorie deficit means you must eat 400 calories less than your maintenance calories. Eating below your maintenance calories is required for weight loss to occur.

Your maintenance calories are the number of calories that allow you to maintain weight. 

For example, if I’m eating an average of 2300 calories per day and my body weight is staying relatively the same, then 2300 calories per day is my maintenance. Therefore, anything less than 2300 calories would be considered a deficit.

A 400-calorie deficit means that I am 400 calories below my maintenance, meaning that I would take in 1900 calories per day.

Achieving a 400-calorie deficit can be accomplished by reducing your daily calorie intake (-400cal of food), increasing your daily activity (+400cal of activity), or a combination of the two (-200cal of food + 200 cal of activity). 

I will focus on creating a calorie deficit only by reducing your food intake for this article.

Creating a deficit of 400 calories can be pretty easy and may only require you to adjust the portion sizes of certain foods you usually eat throughout your day. 

For example, if you usually consume 5 meals a day, you could easily achieve this deficit by reducing each meal by 80 calories.

One pound of fat is equal to around 3500 calories. Therefore, if you create a 400-calorie deficit daily, you could expect to lose just under 1 pound per week.

Is A 400-Calorie Deficit Healthy?

Eating at a deficit of 400 calories is healthy as long as you’re not already underweight because it is not extreme enough to result in any adverse side effects that would affect your overall health.

That being said, even though a 400-calorie deficit is considered a healthy deficit, you shouldn’t be in a deficit for a prolonged period. The recommended amount of time spent in a 400-calories deficit is around 8-12 weeks to achieve the best fat loss results.

If you decide to remain in a calorie deficit for too long, you could experience negative side effects such as a reduction in your metabolism (your body’s ability to burn calories), nutrient deficiencies, low energy, reduced immunity, and a potential loss of muscle mass.

If you notice some of these side effects before the 12-week mark, it is important to listen to your body and start reverse dieting out of your calorie deficit back to your maintenance calories.

Should You Use a 400-Calorie Deficit?

A 400-calorie deficit can be a great tool for anyone who is currently eating at their maintenance calories or in a surplus (more calories than you need to maintain weight), and wishes to lose weight in a sustainable and healthy way. 

If you are considering entering a calorie deficit phase, it is important to ensure that you are eating enough before reducing your calories.

For example, a 25-year-old male who is 5’11”, weighs 195 pounds, and takes part in moderate exercise 4-5 times a week would need to eat around 2750 calories a day to maintain his weight.

If he wanted to lose weight, he could reduce his intake to 2350 calories per day. This would result in him losing between 5-10 pounds in around 10 weeks.

However, if this male should be eating around 2750 calories to maintain his weight, but in reality, he’s only able to maintain his weight at 2200 calories, then he should not reduce his calories further.

If you are already eating fewer calories than your body burns in a day, then you should not create a further deficit but rather focus on building your calorie intake back up to maintenance by reverse dieting.

What Can You Expect From a 400-Calorie Deficit?

What can you expect from a 400-calorie deficit Pros vs Cons

If you choose to eat at a 400-calorie deficit and it’s healthy for you to lose weight, then there will be more benefits than drawbacks.

However, if you implement a 400-calorie deficit while already undereating, there will be more negative outcomes than positive ones. 

400 Calorie Deficit Pros

1. Fat Loss

The main benefit of a 400-calorie deficit is that it will help you lose weight by forcing your body to use its own resources (preferably fat) for fuel because fewer calories are coming in. 

As long as you are consistent with your 400-calorie deficit, you should lose weight at a healthy and sustainable rate.

If you pair your calorie deficit with weight training, you will also increase your potential to maintain or even build lean muscle mass.

The more muscle mass you have while dieting, the better because it increases your metabolism (which means more fat burn) and improves your physique.

2. Lowers Cholesterol Levels

Another benefit of a 400-calorie deficit is that it can help you lower your cholesterol levels, reducing your risk of heart disease.

While not everyone struggles with high cholesterol levels, eating at a calorie deficit can help to maintain already healthy cholesterol levels. 

In addition to the types of fat you eat in your diet (unsaturated > saturated), losing weight has been shown to play a large role in healthy cholesterol levels.

3. Reduced Inflammation In The Body

A 400-calorie deficit can also be beneficial for reducing inflammation in the body, which is important because high levels of inflammation in the body often contribute to chronic diseases.

Combining a healthy caloric deficit with a diet plentiful in omega-3 fatty acids is the perfect recipe for reducing inflammation.

400 Calorie Deficit Cons

1. Potential Muscle Loss

While the ultimate goal of a calorie deficit is to lose fat, it is important to remember that whenever you’re in a calorie deficit, there is also the potential to lose muscle as well.

Although you are less likely to lose a significant amount of muscle on a modest 400-calorie deficit, there are some things you should be doing to help reduce your risk of losing lean mass, like eating enough protein (1g of protein per pound of bodyweight) and strength training.

For example, A female weighing 160lbs should aim for 160g of protein per day and either keep up with her current strength routine or start strength training 2 days per week.

2. Reduced Energy

When your body receives less fuel than it normally burns in a day, over time, a slight reduction in energy is inevitable. While this is considered somewhat normal in a deficit, you don’t want your energy to dip too low.

If you do experience an extreme dip in energy, you may have created a deficit that is too severe, or you have been in a deficit for too long. If this is the case, consider increasing your calories back to maintenance for some time to allow your body to recover.

3. Increased Hunger

When you are reducing your calories, a bit of hunger is almost unavoidable. While some hunger during a calorie deficit is normal, hunger levels should not become unmanageable. 

Increased hunger can typically be managed by eating more high-fiber, high-volume foods and drinking plenty of water. However, if you start experiencing more extreme levels of hunger, it’s likely a sign that you should increase your calories.

4. Slower Metabolism

Unfortunately, when calories are reduced, the body will often respond by reducing the rate at which you burn calories to preserve energy for basic bodily functions.

This means that your body adapts to maintain its weight with fewer calories by reducing its energy output.

Reductions in metabolism are unavoidable over time, so eating in a deficit should be short-lived, and reverse dieting is necessary for future weight loss success.

For example, if my maintenance calories were 2300 before dieting, but are now 1900 calories, then I would have to eat less than 1900 calories to lose weight, whereas before, I only had to eat less than 2300 calories.

Rather than continuing to let my maintenance get lower and lower, I should reverse diet so that I can lose weight on more calories in the future.

How to Achieve a 400-Calorie Deficit

How to achieve a 400-calorie deficit

To achieve a 400-calorie deficit, you can follow these steps:

  • Step 1: Determine your TDEE
  • Step 2: Subtract 400 calories from TDEE
  • Step 3: Choose the best ways to eliminate 400 calories
  • Step 4: Make sure you are tracking calories accurately

Step 1: Determine Your TDEE

If you want to create an accurate calorie deficit, you must first know your Total Daily Energy Expenditure of calories (TDEE).

Your TDEE represents the number of calories you burn per day, which would be equivalent to your maintenance calories.

If you burn 1900 calories per day, then your maintenance calories should also be 1900 calories so that your energy balance equals out and you maintain your weight.

The easiest way to find your TDEE is using an online calculator like this one.

For example, a 30-year-old, 135-pound woman who is 5’4” tall and exercises 4-5 times a week had a TDEE of around 1900 calories per day.

Step 2: Subtract 400 Calories From TDEE

Once you have determined your TDEE, you can subtract 400 calories from this number to determine your new calorie deficit.

For example, the woman above would subtract 400 calories from her regular maintenance calories of 1900, making her new deficit around 1500 calories.

Step 3: Choose the Best Ways to Eliminate 400 Calories

The next step after you have determined your calorie deficit is to determine which foods you will reduce or eliminate to create your 400-calorie deficit.

This will vary greatly depending on what you eat in a day and what you would prefer to eliminate from your diet.

I recommend trying to eliminate calories from food sources that do not provide a lot of volume, nutrients, or fiber since these do not contribute as much to you feeling full.

For example, eliminating the following calories from your day will easily put you in a 400-calorie deficit without having to restrict food quantities extremely.

● Eliminate the cream and sugar and your coffee (equal to 50-100 calories)

● Cook your vegetables in water instead of oil (2 Tbsp is equal to roughly 240 calories)

● Switch out your glass of orange juice for water (2 cups of orange juice is equal to roughly 200 calories)

Step 4: Make Sure You Are Tracking Calories Accurately

While the steps above are critical to creating a 400-calorie deficit, none will matter unless you are properly tracking your calories throughout the day because if you don’t know how much you’re eating, you won’t be able to be consistent with your deficit.

One of the best apps that you can use to track your daily calories accurately is MacroFactor. Use this link and enter the code FEASTGOOD when signing up to get an extra week on your free trial (2 weeks in total). Cancel any time before your trial ends without being charged.

Is A 400-Calorie Deficit Worth It? My Practical Advice

Is a 400-calorie deficit worth it? My practical advice

If your maintenance calories are sufficient and you have the goal of losing weight, then going into a 400-calorie deficit for a period of time is most definitely worth it to help you reach your target.

With that said, there are a few things that you should consider whenever you are planning to enter into a calorie deficit:

1. Eat Enough Calories Before Entering a Deficit

If you are planning on entering a calorie deficit, it is recommended that you eat your maintenance calories for at least an 8-week period before reducing your calories.

If you are a chronic dieter, and you are not giving your body this proper amount of time to recover between deficits, you will likely experience negative side effects of undereating and fail to achieve the results that you want.

2. Prioritize Whole Foods

While in a calorie deficit, prioritizing whole foods which are higher in fiber, nutrients, and volume is critical to your health.

This will help to ensure that you don’t experience any nutrient deficiencies while dieting, along with helping with the feeling of fullness and encouraging proper digestion.

3. Focus on Other Healthy Habits

Since a calorie deficit can be stressful for your body, focusing on other lifestyle habits to help your body recover from this stress will help you to achieve better results.

A few things you can do to help your body recover and minimize stress levels are:

  • Prioritize a good night’s sleep
  • Take part in daily activities that help relieve stress (nature walks, reading a book, yoga, and meditation).
  • Don’t put too much on your to-do list, and allow time for rest and relaxation

4. Listen to Your Body and Reverse Diet if Necessary

Even though a 400-calorie deficit is considered healthy, if you are experiencing negative side effects that are affecting your quality of life, you need to listen to your body and either reduce your calorie deficit or go back to eating your maintenance calories to restore energy.

If 400 calories feel like too large of a deficit for you, try eating at a deficit of 200 calories to see if this lessens the severity of the negative symptoms.

Frequently Asked Questions

How Much Weight Can You Lose on a 400 Calorie Deficit?

If you eat at a 400-calorie deficit consistently, you will lose anywhere from 0.5 to 1 pounds of bodyweight per week.

While the exact amount lost will depend on the person, this is a safe amount of weight to lose and will be more sustainable than more rapid weight loss.

Is a 400 Calorie Deficit Safe?

As long as you have been eating at maintenance calories before your dieting phase, eating at a 400-calorie deficit is considered safe to achieve your weight loss goal.

While you will still see results, this deficit is not severe enough to experience extreme negative side effects that come with undereating.

Can You Stick to a 400 Calorie Deficit Long Term?

You shouldn’t be in a 400-calorie deficit for an extended period (>12 weeks) because of reductions in energy, metabolism, and muscle mass that occur with weight loss.

For the best results, you should aim to be in a calorie deficit for no longer than 8 to 12 weeks before returning to maintenance calories.

What To Read Next:


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White AM, Johnston CS, Swan PD, Tjonn SL, Sears B. Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: a pilot study. J Am Diet Assoc. 2007 Oct;107(10):1792-6. doi: 10.1016/j.jada.2007.07.009. PMID: 17904939.

Willoughby, D., Hewlings, S., & Kalman, D. (2018). Body Composition Changes in Weight Loss: Strategies and Supplementation for Maintaining Lean Body Mass, a Brief Review. Nutrients, 10(12), 1876. https://doi.org/10.3390/nu10121876

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Pahwa R, Goyal A, Jialal I. Chronic Inflammation. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493173/

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About The Author

Colby Roy

Colby Roy is a holistic health and nutrition coach. She is certified through Precision Nutrition and has a passion for all things nutrition and healing the body. More specifically, Colby likes to work with clients who want to optimize their gut health and energy levels.

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