How many calories should you eat to lose weight fast?

Use the calculator on this page to determine how many calories you should eat, if you want to lose weight fast.

The calculator uses the Mifflin-St Jeor formula which is a relatively new equation for accurately predicting calorie requirements in individuals.

Gender Age Weight Switch to lbs Height Switch to feet and inches Activity Level

This calculator will never show a number below 1000 calories per day. Please speak to a qualified health professional before attempting to eat less than that.

If the results surprise you and seem difficult, don’t worry you’re not alone. When ever I’m trying to lose weight fast I have to cut my calories quite a bit. In order to fend off hunger and keep my energy up I take a special type of green tea called matcha, which is packed with EGCG (the stuff shown to help weight loss), but it’s also packed with a precise dose of caffeine, without the junk from energy drinks.

There are lots of possible diet plans to get results. For me, and for most people I know, using the Keto Diet produces by far the best results (this site gives a good overview). It’s low carb and high fat, which might sound counter-productive but the results can be amazing. It can reset insulin resistance in the body (fancy way of saying your body will process carbs better). Since most extra weight has to do with insulin problems, keto can be a dream.

Warning though, the first week or two of keto can be… well ugh… rough. Low energy and hunger. The problem is that your body has to get used to burning fat for energy, using what are called ketones. This process can take a little bit. I’ve found that I get into ketosis MUCH quicker if I take 1-2 scoops per day of an exogenous ketones powder (I use this one), which is a nice shortcut to ketosis.

Understanding Calories

A calorie is a unit of energy. In nutrition terms, calories are used to determine the amount of energy you consume (through eating) and expend (through exercise and daily activities). For example, 1 medium banana contains approximately 105 calories. Jogging at an average pace for about 15 minutes would burn an equal amount of calories, meaning all the energy you would have consumed from that banana would have been used up.

Your Basal Metabolic Rate (BMR) is the number of calories your body needs everyday in order to function, whilst maintaining your current weight. Everyone’s BMR is different and yours depends on a number of factors:

  • Your current weight and height – a taller and generally larger person requires more energy on a daily basis than a shorter and smaller person. However the amount of muscle you have is also a factor. Two people could be the same height and weigh the same, but the person with more muscle will have a higher BMR.
  • Age – as you get older, your metabolism slows down and this means you use up less energy than a younger person. This is mainly because you start to lose muscle with age. That being said, if you work out regularly, you will have more muscle mass than someone who does not.
  • Gender – on average, men tend to have more lean muscle mass than women and so their BMR tends to be slightly higher than that of women.

Your Total Daily Energy Expenditure (TDEE) is your BMR together with the total number of calories you use up throughout the day, from activities such as doing the housework, walking or going to the gym. The TDEE of a person who leads a sedentary lifestyle (someone who barely exercises), will be much lower than someone who leads a very active lifestyle (exercises intensely, 6 – 7 days a week). This makes sense because you burn a larger amount of energy when you exercise.

The calculator at the top of this article will give you a fairly accurate estimation of the number of calories you need to consume everyday if you want to maintain your current weight, lose weight at a normal pace or lose weight fast. It takes into account all of the factors mentioned above.

So for example, a 40 year old female who is 165 cm tall, weighs 75 kgs and is moderately active (exercises 3 – 5 days per week) will need to consume approximately 2200 calories to maintain her weight, 1800 calories to lose weight at a normal pace (80% of her TDEE) and 1300 calories to lose weight fast (60% of her TDEE).

Compare that to a person who is the same age, gender, height and weight but who leads a sedentary lifestyle – they will need approximately 1700 calories to maintain their weight, 1400 calories to lose weight at a normal pace and 1000 calories to lose weight fast.

To lose weight fast, you need to make sure that the number of calories you consume is less than your TDEE. Doing so will force your body to use its fat stores as a source of energy.

Calories in different foods


Different foods have different amounts of calories. For example, compare 100g of apples to 100g of kidney beans. The apples contain 52 calories in total, whereas the kidney beans contain 333 calories. That is a big difference, with the kidney beans containing more than 6 times the calories of the apples. (It is important to keep in mind that just because a certain food is high in calories, it doesn’t necessarily mean it should be avoided completely. There are plenty of filling high calorie foods that, when eaten in moderation, can help you to lose weight. I mentioned the kidney beans and apples example just to make the point that it is often quite difficult to accurately determine the number of calories in a food off the top of your head.)

So when you eat a certain food, you may think it isn’t packed full of calories but you could be wrong. There a number of different online tools and mobile apps that can help you determine the amount of calories you are getting from certain foods:

  • Our healthy food finder, which lets you compare the amount of calories and nutritional profiles of up to 3 different healthy foods.
  • My Fitness Pal – a great website where you can enter almost any food you want and it will tell you how many calories it contains. It is also available as an app both on Android and iOS. The great thing about the app is that it has a barcode scanner, so you can use your smartphone’s camera to take a picture of a food items barcode and it will tell you how many calories that food contains.

Using a calorie counter when just starting out on your weight loss journey is highly recommended because it gives you an idea of how many calories you are currently consuming and lets you decide the portion sizes and types of foods that you should be consuming.

It is important to note that cutting large amounts of calories is not always an easy task. Reducing your daily caloric intake by 400 calories will be much easier to do than reducing it by 1000 calories. The point I am trying to make here is yes, you can lose weight fast, but at the same time you need to set realistic goals.

Rather than just restricting calories, you should also increase your activity levels. This allows you to lose weight in a healthy manner. For example, if your goal is to achieve a net deficit of 600 calories, one option would be to reduce your caloric intake by 400 calories and then burn 200 calories via exercise.

Another thing to note is to never reduce your minimum caloric consumption to less than 1000 – 1200 calories, without being supervised by a qualified health professional. Sure, you want to lose weight and cutting calories is the best way to do this; but consuming anything below the bare minimum number of calories can cause a vast number of health problems. Not only that, consuming too few calories can slow down your metabolism and deter weight loss. Always speak to your doctor before making drastic changes to your diet or exercise routine.

Easy ways to create an effective net caloric deficit

Simply cutting calories without a plan is not a good idea. Doing so will either leave you feeling very weak or extremely famished, and neither are pleasant. Instead, you should make intelligent and scientifically backed choices about the foods you do and don’t eat.

Eat more protein


The food you eat is made up of 3 main macronutrients: protein, carbohydrate and fat (learn more here). Out of all 3, protein has the highest satiety, which means it makes you feel the most full. If you eat the same amount of lean chicken and pasta, the chicken is likely to leave you feeling fuller for longer. And that means you end up eating less in the long run.

There have been scientific studies to prove this. In this study for example, 19 participants consumed a diet made up of 15% protein, 35% fat and 50% carbohydrate for 2 weeks. They then increased protein consumption to 30%, reduced fat consumption to 20% and kept carbohydrate consumption at 50%.

The results showed that the increase in protein meant that the participants on average ate 441 fewer calories per day! This result is very impressive; as mentioned above, trying to cut calories can be quite a challenge, but by simply eating more protein rich foods, you can achieve this without even having to try.

Protein consumption has also been shown to increase your metabolic rate and reduce food cravings. Great protein sources include chicken, turkey, salmon, nuts & seeds and beans. If you are vegetarian or vegan, here are some protein rich foods you can add to your diet.

Cut down on carbohydrates, especially the unhealthy ones


Refined carbohydrates and sugary foods such as cakes, doughnuts and french fries are best avoided when trying to lose weight (and generally as well, if you want to have a healthier body).

Research has also proved that reducing carbohydrate intake and increasing protein intake causes people to feel less hungry and so they end up eating less. Other studies have shown that low carbohydrate diets are very effective when trying to lose weight.

That being said, don’t switch out carbohydrates from your diet completely. Carbohydrates are important for your body as they are a source of energy and also provide essential vitamins and minerals. What you want to do is switch unhealthy carbohydrates for healthy ones. So for example, have brown rice instead of white rice and fruit instead of sugar filled desserts.

Drink more water and fewer soft drinks


You may be consuming a ton of calories without even realising it. Soda, store bought juices and shop bought coffee are usually full of sugar; this translates into calories. For example, a 300ml bottle of cola contains about 120 calories and is full of refined sugar, which is a leading cause of obesity, diabetes and metabolic syndrome.

When you eat food, your stomach fills up – your brain is able to sense this and so it can tell you when to stop eating (i.e. you get a feeling of ‘being full’). But when you drink soda, you are consuming calories in liquid form but your brain does not register this as efficiently. Studies have shown that as a result, you don’t eat less food and so could end up in a calorie surplus. This is not what you want when trying to lose weight fast!

Now compare that to good old water – it contains 0 (yes that’s zero) calories and is by far a healthier option, as it does not contain any added sugar, artificial flavour or preservatives. Drinking more water has been shown to increase thermogenesis, which translates to more calories being burned by your body. One study even showed that drinking half a litre of water half an hour before a meal resulted in a 44% increase in weight loss over a 12 week period.

You may not like the taste of plain water and so tend to drink less of it. There’s an easy fix to this – simply add a few slices of lemon, orange or cucumber to your water to give it some flavour. You can also increase your water intake by consuming it in the form of coffee, green and herbal teas. Just make sure not to add any sugar!

Exercise more


Whenever you move, you burn calories. The faster and more intensely you move, the more calories you burn. So it makes sense that if you want to burn more calories, you should increase the amount you exercise. Both cardiovascular and weight training will help you burn calories.

When you exercise, you build lean muscle. And the more muscle you have, the higher your metabolism will be, which means you will burn more calories. It ends up being a positive cycle. Some of the best exercises you can do to grow your muscles include squats, dead lifts, bench presses and pull ups.

If you are just starting out, take it easy to begin with and then slowly increase the intensity at which you exercise.

One thing I would like to point out is to use body measurements and a mirror rather than a weighing scale to determine if you are losing weight. As mentioned above, when you exercise, you burn off fat and build muscle. But the same volume of muscle weighs more than fat. So on a weighing scale it may seem as though you are losing less weight than you would want to, but the truth is that you have essentially “converted” unhealthy fat into healthy muscle, which is a good thing.

You have to set realistic goals. Setting a goal of trying to lose 60 pounds in one month will only leave you disappointed. Everyone is different and when trying to lose weight, your genetic make up is also a factor.

By consuming a healthy, balanced and protein rich diet, exercising more and staying in a calorie deficit, you’ll start losing weight in no time. Best of luck!

For more weight loss tips, check out our article here.

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