The single most important factor for weight loss is calorie control, period. It is basic biology and also physics. If you eat fewer calories than your body needs you will lose weight. But how can you learn exactly how many calories you need each day?
Here is everything you need to understand calorie control and estimate your exact calorie needs for weight loss. Use this simple calorie calculator to get started:
At the simplest level, your body runs off energy in the form of calories from foods and beverages. Calories = energy. And you need this energy to fuel your daily needs and to just plain survive. If you stop eating calories, you will eventually die.
So what does survival have to do with losing weight? Well, because calories are so important for living, your body has a way to store them as muscle and fatty tissue - which is also the exact type of weight you are able to lose, gain or maintain. This storage form acts as a reserve fuel for times you are not getting calories directly from food, and as a safety measure just in case you aren't able to eat again for a while.
Creating a Calorie Deficit
If the amount of calories you eat is equal to the number of calories you burn, you will maintain your current weight. If you eat less, you will use more reserve fuels for energy and lose fat and muscle weight. And if you eat more, you store more reserve fuel and gain muscle and/or fat. This is the calorie balance equation for weight management: calories in versus calories out.
There is no pill, special diet or food that is able to hack your metabolism and change this basic formula. No matter how much fat or how many calories you burn for fuel, you cannot lose weight or lose fat unless you eat less than what you burn through a consistent calorie deficit.
What is a Calorie?
When it comes to nutrition, there is no single discovery more valuable than a calorie as it relates to energy intake and expenditure. Calories allow us to quantify our food, compare different foods and manage individual nutrition and fitness needs. But what exactly is a calorie?
Technically speaking, a calorie is the amount of energy needed to raise the temperature of 1 kg of water 1 degree Celsius. Or in other words, it is a unit of measurement that tells us how much energy is in our food. Initially, calories were measured by placing a food item in a sealed container and submerging it in water or burning the food. Today, calories are estimated using the food macronutrient breakdown, or in other words, the number of carbs, fat, and protein a food contains (2).
Calories have long been used as a measurement of heat, dating back to the early 1800s. But what we know and recognize as a food calorie today was not established until sometime around the 20th century (3). To this day, calories remain the most efficient way to measure energy intake and output, and the best way we know of to directly affect weight management.
Macros = Calories
Food and drinks are made up of macros - carbohydrates, protein, and fat - that supply all of the calories we eat. Each macro has a different role when it comes to health and nutrition and also provides a different number of calories per each gram (protein and carbs = 4 calories per gram, fat = 9 calories per gram).
Because macros play a role in your health and energy intake, tracking your macros is an efficient way to count calories and balance your nutrition intake.
Micronutrients, such as vitamins and minerals, also play a role in overall health and weight management but they do not directly contribute to calorie intake. In other words, you don't get any calories from the vitamins and minerals that you eat or drink.
Even though many micronutrients are involved in metabolic processes that help you get energy and can sometimes make you feel more energetic (I'm looking at you B12), they cannot increase your energy alone; you still need calories from macros for this.
How Many Calories Do You Need?
Energy needs are completely individualized which is part of the reason why calorie control works so well for weight loss - there is no one size fits all approach to how much energy your body needs. Calorie needs can vary depending on age, height, gender, weight, percent lean muscle mass and level of activity.
Your daily needs are made up of four major components, BMR, NEAT, TEA and TEF. Together, these comprise your total daily energy expenditure (TDEE), which is a fancy way of saying how many calories you burn each day based on your lifestyle, physical activity, and personal needs.
BMR: What is Basal Metabolic Rate?
Your daily bodily functions - like your heartbeat, brain power, and breathing, all need a certain number of calories to work. This basic amount of calories is also known as your basal metabolic rate (BMR) or resting metabolic rate (RMR). This is the bare minimum of energy you need each day, if you never left your bed or moved around, and accounts for 60% to 70% of your daily calorie requirement.
TEA and NEAT: Activity Energy Expenditure
Assuming you will move around at some point during the day, you will also need to consider calories burned from
What is TEF?
Your total daily energy expenditure is also affected by something called the thermic effect of food (TEF), also called diet-induced thermogenesis (DIT). TEF or DIT accounts for only a small portion, 10% of your total TDEE, but it is still worth noting.
Because TEF is such a small portion of your TDEE, it is not necessary to consider when calculating your overall calorie needs. But it may still be an important factor when considering what to eat for weight loss.
Calculate Your TDEE
You can easily get your TDEE using an online calorie calculator. Or estimate your needs using an activity factor (AF) and known BMR.
Based on how active or sedentary you are each day, use one of the following, or perhaps somewhere in between:
- Sedentary (AF of 1.1) - Little to no exercise.
- Lightly Active (AF of 1.2) - Light exercise or training 1 to 3 days per week.
- Moderately Active (AF of 1.35) - Moderate exercise 2 or more days per week.
- Very Active (AF of 1.4) - Hard exercise 3 or more days per week.
- Extremely Active (AF of 1.6) - Working out 2 or more times a day.
Simply multiply your selected activity factor and BMR together to get your TDEE.
TDEE = BMR x AF
How Many Calories Should I Eat to Lose Weight?
I know what you're thinking, cutting as many calories as possible is the best way to quick weight loss. But trust me on this, you are going to be much happier and more successful in the long run if you only cut 15 to 20% of your calories or less. Starving yourself might work temporarily, but it certainly isn't going to be sustainable or even enjoyable for that matter. And you may end up gaining all the weight back and then some.
Start with one of the following for at least three weeks and then reassess your needs:
Sustainable Weight Loss = TDEE x 0.85
Fast Weight Loss = TDEE x 0.8
If you find that after dieting for some time, you are no longer losing weight, it might just be time to give yourself a break. Take a couple of weeks off your diet and let your calories creep up just a little. If you've lost some weight, you probably have to recalculate a new TDEE to maintain your new normal. And then after a little bit of time adjusting, you can get back to cutting calories if you still need to lose more weight.
Whatever you do, don't rush it or push your body too hard. Remember this is survival fuel we are talking about here. And your personal wellbeing is just as, if not more, important than the number on the scale. You will reach your goals, you will make progress and you will see results, you just need to be consistent and give yourself time.
How Many Calories Are in a Pound?
Wondering how much you need to cut in order to lose one pound? Well, there are roughly 3,500 calories in a pound of fat, so you would need to cut this amount from your diet through food or exercise to lose one pound.
This number will also give you a good gauge of how fast you are able to lose weight since there are only so many calories you can cut or burn each day. If you spread out 3,500 calories throughout the week - 500 calories a day - you can expect to lose about a pound a week. But again this depends on many individual factors and is not a perfect science.
How to Make Your Calories Count
Weight loss is a numbers game, but there are a few things you can try to make your journey more bearable and give you even better results by either focusing on the types of foods you are choosing, getting your mental health in check, and opting for the most efficient forms of exercise for weight loss.
Your body needs
The overall balance and nutrition of your diet can affect the type of weight you lose, gain or maintain. If your macro balance is out of whack, you could be storing more fat or losing muscle mass, which can hinder your overall efforts.
In addition, eating more nutrient-dense foods may help you control hunger (5). When your body is not getting the nutrition you need or is deficient in key nutrients, it signals to your brain that you need to keep eating, regardless of how much you've eaten.
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