So, your calorie deficit isn’t working. 

Before you switch gears to a new diet or workout plan, it’s important to figure out why your current plan isn’t working. There are a few reasons why your weight loss efforts might not be leading to your desired results. Understanding what’s underlying your stalled weight loss can help you get back on track, shake the plateau, and hit your weight loss goal. 

In this article, we’ll cover 8 reasons your calorie deficit isn’t working – and what you can do instead. 

What is a calorie deficit?

A phone screen displaying a calorie tracker app is held over a kitchen counter on which fresh fruit and vegetables are visible.

A calorie deficit means you’re consuming fewer calories than you’re expending. 

While this might sound simple, there are plenty of ways to get tripped up when calculating a calorie deficit. It’s common for calorie-related misunderstandings to forestall weight loss progress. If you’re confused about how to calculate calories in vs. calories out accurately, the MVM BMR & TDEE calculator is a great place to start. 

How do I calculate a calorie deficit?

Calculating a calorie deficit starts by understanding how many calories you need to maintain your current weight. This is known as your Total Daily Energy Expenditure (or TDEE for short). 

Your TDEE is made up of: 

  • BMR (Basal Metabolic Rate): The calories you burn at rest.
  • TEF (thermic effect of food): The calories you burn from processing food. 
  • TEA (thermic effect of activity): The calories you burn from activity.

If you consume the same number of calories each day as your TDEE, you will maintain your current weight. If you eat fewer calories than your TDEE, you’ve created a calorie deficit and will lose weight. Similarly, if you eat more calories than your TDEE, you’ve created a calorie surplus and will gain weight.  

For example, if you have a TDEE of 2000 kcal, then: 

  • Consuming 2000 kcal daily would lead to weight maintenance
  • Consuming >2000 kcal daily would lead to weight gain
  • Consuming <2000 kcal daily would lead to weight loss 

You can calculate your BMR and TDEE by using an accurate TDEE calculator.

If you’ve created a caloric deficit and aren’t seeing the results you’re looking for, then make sure to check out the 8 reasons your calorie deficit isn’t working later in this blog. 

How much of a calorie deficit do I need to lose weight?

Any consistent calorie deficit will lead to weight loss. However, the size of your deficit will dictate how quickly (or slowly) you lose weight. A larger deficit will lead to quicker weight loss – up to a point. Contrary to popular opinion, creating a larger calorie deficit doesn’t always lead to faster weight loss. Our bodies are efficient at conserving energy, and too great of a deficit can lead to “compromises” in other areas, leading to fatigue, lowered immunity, muscle loss, or brain fog. You can read more about this and other fat loss FAQs here. 

What’s the best calorie deficit for weight loss?

The best calorie deficit for weight loss is one you can consistently maintain. 

A daily calorie deficit of approximately 400-500 kcal is considered a good starting place for a weight loss plan. With any deficit, check in after sticking to it consistently for 4 weeks. If you’re not happy with your results, are experiencing excessive hunger, or are losing weight very quickly or slowly, it may be time to adjust your caloric intake. 

How much of a deficit do I need to lose 1lb per week?

Losing 1lb per week requires a weekly calorie deficit of 3,500 kcal. This is the equivalent of a daily caloric deficit of 500 kcal.

Let’s take a couple of examples:

Person A has a BMR of 1700 and a TDEE of 2400. A caloric deficit of 500 kcal would leave Person A with a calorie goal of 1900 kcal per day. This amount is over their BMR and should lead to an approximate weight loss of 1lb per week. 

Person B has a BMR of 1250 and a TDEE of 1600. If Person B were to maintain a caloric deficit of 500 kcal, this would give them a daily calorie goal of 1100 kcal. This would put them below their BMR, which would likely be unsafe. Person B could either: 1) add exercise to their routine to increase their TDEE or 2) maintain a smaller caloric deficit. Both options would keep Person B above their BMR, but Option 1 would come with all the added benefits that exercise provides

Why isn’t my calorie deficit working?

A dark-skinned, curly-haired woman looks at her phone while blending fruits and vegetables to create a healthy smoothie.

Now that we’ve covered the basics of how to create a calorie deficit, it’s time to consider why you might experience your calorie deficit not working. 

Reason 1: You’re not in a true calorie deficit 

The most likely reason your calorie deficit isn’t working is that… you’re not in a calorie deficit. 

Reducing the amount you eat, cutting out certain foods or food groups, or making healthier food choices are all common strategies for losing weight – but they don’t necessarily create a calorie deficit and therefore weight loss.  

Without tracking your food intake, it’s very difficult to determine whether or not you’re maintaining a calorie deficit, and impossible to accurately calculate the extent of that deficit. 

Similarly, it can be difficult to accurately track calories burned through exercise, especially since many fitness watches or calculators tend to overestimate energy expenditure. A Stanford study that investigated the accuracy of 5 different fitness trackers for heart rate and energy expenditure found that while trackers tend to accurately track heart rate (with a median error of less than 5%), not a single device accurately estimated energy expenditure. The median error of the trackers ranged from 27.4% (for the Fitbit Surge) to 92.6% (for PulseOn) – massively outside of the acceptable error range. 

Without an accurate idea of how many calories you’re taking in (through food and beverages) and burning off (through exercise and daily activity), it’s understandably very difficult to maintain a calorie deficit!

If this is you, then there are steps you can take to accurately assess your caloric needs and calculate a suitable caloric deficit to achieve your weight loss goals: 

Need more detail? Read our guide on how to lose fat with a DEXA scan.  


Reason 2: You aren’t tracking your intake (accurately)

A bowl of oats sits on top of a digital kitchen scale which reads 313g.

Research consistently shows that we’re not accurate reporters of our food intake. Self-reported food intake is often very inaccurate, and many of us tend to (sometimes drastically) underestimate the number of calories we consume. 

With this in mind, if you want to lose weight then it’s important to accurately track what you’re eating to ensure you’re maintaining a calorie deficit. There are plenty of methods for doing so, such as popular calorie-tracking apps like MyFitnessPal and Cronometer.

If you’re tracking your food and still not losing weight, make sure to: 

  • Use a digital food scale to measure food quantities
  • Record all snacks, drinks, and alcoholic beverages
  • Track in the moment – don’t rely on your memory!
  • Get to grips with portion size
  • Track the exact food – not a generic brand or quantity
  • Use the barcode feature of the tracking app, if it has one
  • Prioritise whole foods and those that create greater satiety

Reason 3: You don’t have an accurate BMR or TDEE calculation

A screenshot of the MVM BMR calculator reads "Your Basal Metabolic Rate is: 1662". Further text described the accuracy of the figure and how to get a more accurate BMR figure.

One of the most common reasons you might not be losing weight is that you’re working with the wrong starting number. Most online BMR and TDEE calculators are notoriously vague, meaning you might not have the information you need to create a calorie deficit. 

Here at My Vital Metrics, we’ve custom-built a BMR and TDEE calculator to provide you with the most accurate figures possible. Unlike most online TDEE calculators, ours takes into account the types and quantities of exercise you do, the type of job you work, the amount of sleep you get, and more. 

If you’re looking for an even more accurate analysis of your caloric needs, a DEXA scan or Resting Metabolic Rate (RMR) test is a great way to take the guesswork out of your weight loss journey. 

Reason 4: You’re retaining water or on your menstrual cycle

If the scale isn’t budging – or is even going up – while you’re maintaining a calorie deficit, this doesn’t necessarily mean you’re gaining weight. 

There are a range of factors that influence the number we see on the scale, including weight from fat, muscle, other body tissues, water, and food travelling through the digestive system. 

Hydration, in particular, can influence our weight – this is why it’s recommended to weigh yourself first thing in the morning, before food or drink. While water is a big part of our total weight, when we talk about “water weight” in the context of weight loss we’re usually talking about something a little more specific. 

After consuming carbohydrates, the body stores carbohydrates as glycogen – a type of glucose used as energy in the body. Each gram of glycogen binds to 3-4g of water. So, when glycogen stores are high, water retention is higher to support this. On the flip side, when glycogen stores are depleted (after exercise, first thing in the morning, or on a lower-carb diet), water weight can drop. If you’re seeing big fluctuations in your weight, water retention could be the cause. Rather than focusing too much on daily fluctuations, prioritise a weekly weigh-in to get the bigger picture on any changes. 

Similarly, it’s normal to see a change of +3-5 lbs during a menstrual cycle. This can be linked to hormonal shifts, water retention, gastrointestinal issues, a decrease in magnesium, or food cravings. Usually, this weight gain will correct itself shortly after. 

Reason 5: You’re experiencing body recomposition

Not all weight loss is fat loss, and not all fat loss is going to show up as a shift on the scale. 

If you’re maintaining a calorie deficit while working out, especially if you’re new to strength training, you may be gaining muscle and losing fat simultaneously. This can look like you’re not making progress – if you focus on the scale. Body recomposition has a host of health-related benefits, and can positively impact your metabolism, aiding future weight loss. 

However, outside of this scenario, gaining muscle and losing fat at the same time isn’t common or can be hard to achieve. If you’re not seeing the scale shift and want to assess your body fat percentage or overall body composition, a DEXA scan is the best way to accurately do so. 

Reason 6: It’s too soon to see weight loss results 

Another reason you might not be seeing weight loss from your calorie deficit is that it’s simply too soon to see results. 

At a rate of 0.5-1lb of weight loss per week, weighing in daily – or even weekly – isn’t likely to show a significant shift on the scale. Once you add in some of the other factors we outlined above (water retention, hormonal fluctuations, any inaccuracies in your tracking), it’s easy to see why someone might be discouraged at the start of a weight loss plan. 

We have to remember also that the body likes ‘homeostasis’ meaning that it tries to keep everything the same. This might mean that you don’t see any movement on the scales for the first few weeks while the body adjusts to the new deficit.

When it comes to weight loss, consistency is key. The changes will come! As you track your weight loss, remember that the scale is just one way of many to assess your progress. Measurements, the way your clothes fit, and the way you feel in your body can all be useful indicators along the way. For the most accuracy, a DEXA scan can offer accurate insights into any changes in your body composition. 

Reason 7: You’re over-exercising, losing muscle, or stressed

If you’re frequently stressed, not getting enough quality sleep, or over-exercising, this could be the cause of your weight loss plateau. 

Excess cortisol from high stress can hinder weight loss by inhibiting the breakdown of fat, as well as impacting dopamine levels that can lead us to seek out foods higher in sugar, salt, or fat. Keeping stress levels in check through regular social interaction, engaging in meaningful activities, or practising yoga or meditation can have a positive impact on your weight loss journey. 

Similarly, sleep plays a key role in the regulation of leptin and ghrelin – the two “hunger hormones”. Getting less than 6 hours of sleep a night tends to increase appetite, as well as lead to poorer food choices. Prioritise getting enough sleep to help keep your weight loss on track. 

Finally, while exercise can and does benefit weight loss, overdoing it can have the opposite effect. Overtraining can spike cortisol levels and lead to higher stress, contribute to fatigue and moving less in the days to follow and lead to over-compensating for the training by eating more. Incorporating regular strength and cardio exercise into your routine will be more beneficial to your weight loss than following a cycle of over- and then under-exercising.  

Reason 8: Medication or an underlying health condition is affecting your metabolic rate 

Finally, if none of the reasons above apply to you, you have an underlying health condition, or you’ve been experiencing a significant plateau in your weight loss, it might be worth consulting a medical professional. 

A doctor can help rule out any underlying causes for your difficulty losing weight, including thyroid conditions, PCOS, hormonal imbalances, or prescription medications. However, make sure not to adjust your existing treatment plan or medication regime without first consulting a medical professional.

Ready to create a sustainable calorie deficit?

A group of four young women stand posed in gym clothing with their arms around each other, smiling and laughing.

The best way to set yourself up for a successful calorie deficit is by having accurate BMR and TDEE calculations. 

Check out the free My Vital Metrics BMR & TDEE calculator to estimate your caloric needs. Looking for an even more personalised calorie plan? A DEXA scan for body composition can give you an accurate BMR calculation based on an assessment of your lean mass. You’ll also receive an in-depth report of your body composition, including body fat percentage, body fat distribution, lean mass, and more. 

To find out more about how My Vital Metrics can help you reach your weight loss and body recomposition goals, reach out to the team today.