This is a simple but highly accurate scientific calorie calculator, along with 5 evidence-based tips on how to sustainably reduce calorie intake.
Enter your details in the calculator below to figure out how many calories you should be eating in a day to either maintain or lose weight.
The calculator is based on the Mifflin-St Jeor equation, a formula that has been shown to be an accurate way of estimating calorie needs in numerous studies (, ).
An average woman needs to eat about 2000 calories per day to maintain, and 1500 calories to lose one pound of weight per week. An average man needs 2500 calories to maintain, and 2000 to lose one pound of weight per week.
However, this depends on numerous factors. These include age, height, current weight, activity levels, metabolic health and several others.
A calorie is a unit that measures energy. Calories are usually used to measure the energy content of foods and beverages. In order to lose weight, you need to eat fewer calories than your body burns each day.
Here is a list of free sites where you can insert the foods you are eating to keep track of your calorie intake: 5 Best Calorie Counter Websites and Apps.
All of them are available online and include apps for iPhone/iPad and Android devices.
It is highly recommended to use a calorie counter for at least a few days, to see how many calories, carbs, protein, fat, fiber, vitamins and minerals you are truly eating.
Seeing the numbers like this can often be an eye opener.
Calories are simply a measure of energy.
It is known that in order to gain weight, more calories need to be entering your body than leaving it.
Conversely, if more calories leave your body than enter it, then you lose weight.
That being said, just cutting calories without regards to the foods you eat is usually not a sustainable way to lose weight.
Although it works for some people, the majority of people end up hungry and eventually give up on their diet.
For this reason, it is highly recommended to make a few other permanent changes to help you maintain a calorie deficit in the long term, without feeling starved.
Here are 5 evidence-based diet/lifestyle changes that have been shown to help people lose weight in numerous studies.
When it comes to losing weight, protein is the king of nutrients.
Adding protein to your diet is the simplest, most effective and most delicious way to lose weight with minimal effort.
Because protein requires energy to metabolize, a high protein diet can increase calories burned by up to 80 to 100 calories per day (, , ).
Protein is also the most filling nutrient, by far. One study showed that people who ate 30% of calories as protein automatically ate 441 fewer calories per day ().
In other words, you can easily increase calories out and reduce calories in... just by adding protein to your diet.
Protein can also help fight cravings, which are the dieter's worst enemy.
In one study, 25% of calories as protein reduced obsessive thoughts about food by 60% and cut the desire for late-night snacking by 50% ().
If you want to lose weight, sustainably, with minimal effort, then consider making a permanent increase in your protein intake.
Not only will it help you lose, it will also prevent or at least significantly reduce weight regain, in case you ever decide to abandon your weight loss efforts (, ).
For more details, read this in-depth article about how much protein you should eat.
Bottom Line: Increasing protein intake can boost metabolism, fight cravings and significantly reduce appetite. This can lead to automatic weight loss.
Another relatively easy change you can make, is to eliminate liquid sugar calories from your diet.
This includes sodas, fruit juices, chocolate milk and other beverages that have sugar in them.
These "foods" are probably the most fattening aspect of the modern diet, by far.
This is because liquid calories don't get "registered" by the brain in the same way as solid calories.
For this reason, drinking sugary soda doesn't make your brain automatically compensate by having you eat less of other things instead (, ).
Studies have shown that sugary drinks are strongly linked to an increased risk of obesity, with one study in children showing a 60% increased risk for each daily serving of a sugar-sweetened beverage ().
Of course, the harmful effects of sugar go way beyond just weight gain. It can have disastrous effects on metabolic health and raise your risk of all sorts of diseases ().
There is absolutely NO physiological need for these beverages and the long-term benefits of avoiding them can be enormous.
Bottom Line: It is important to avoid sugary soft drinks and fruit juices, because liquid sugar is the single most fattening aspect of the Western diet.
One very simple trick to increase weight loss is to drink more water.
This can increase the number of calories you burn for up to 90 minutes (, ).
Drinking about 2 liters (68 ounces, or 8 glasses) of water per day can make you burn about 96 more calories per day.
But when you drink water may be even more important, because having it before meals can help reduce hunger and make you automatically eat fewer calories ().
In one study, drinking a half liter (17 ounces) of water a half hour before meals made people lose 44% more weight over a period of 12 weeks ().
When combined with a healthy diet, drinking more water (especially before meals) does appear to be helpful if you need to lose weight.
Bottom Line: Studies have shown that drinking water can boost metabolism. Drinking it a half hour before meals can help you eat fewer calories.
When we eat fewer calories, our bodies compensate by making us burn less.
This is why long-term calorie restriction can significantly reduce metabolism.
Not only that, but it can also lead to loss of muscle mass. Muscle is metabolically active, so this can reduce metabolism even further.
Pretty much the only proven strategy to prevent this from happening is to exert your muscles by lifting weights.
This has been repeatedly shown to prevent muscle loss and prevent your metabolism from slowing down during long-term calorie restriction (, ).
Of course, we don't want to just lose fat... we want to make sure that what is beneath also looks good.
If you can't get to a gym, then consider doing some body weight exercises like push ups, squats, sit ups, etc.
Doing some cardio like walking, swimming or jogging can also be important. Not so much for weight loss, but for optimal health and general wellbeing.
Of course, exercise also has a plethora of other benefits that go way beyond just weight loss... such as a longer life, lower risk of disease, more energy and feeling better every day (, , ).
Bottom Line: Lifting weights is important, because it inhibits muscle loss and prevents the metabolic rate from slowing down.
Cutting carbs is a very effective way to lose weight ().
When people do that, their appetite tends to go down and they eat fewer calories automatically (, ).
Studies have shown that eating a low-carb diet until fullness can make you lose about 2-3 times as much weight as a calorie restricted low-fat diet (, , ).
Not only that, but low-carb diets also have all sorts of other benefits for health, especially for people with type 2 diabetes or metabolic syndrome.
But if you don't want to go low-carb, then that's fine too. Just make sure you eat quality, fiber-rich carbohydrate sources... from whole, single ingredient foods.
If you stick to real foods, the exact composition of your diet becomes less important.