How many calories should I eat to lose weight?
How many calories you should consume to lose weight entirely depends on how much energy you expend in a day. The common intake that dieters tend to select is 1200 and 1500 calories. When I ask where this number came from, the common response is “I guess I heard somewhere that it’s just the number to follow”.
The truth is that these numbers are totally arbitrary. It’s very likely that this intake will put you in a calorie deficit, because they are indeed very low. The issue is that they may be TOO low for YOU. If your total daily energy expenditure (TDEE) is 2500 calories and you’ve gone down to 1500 – worse yet, 1200 – this is a massive shock to the system. This is far too much of a calorie deficit to achieve long term weight loss.
Research suggests that a 10-15% drop in calories is the appropriate reduction for long term sustainable weight loss. When we drop calories, our metabolism will adapt. The best analogy for this is a thermostat in your house. If it’s hot out, your thermostat will turn down the heating, if temperature drops, the thermostat kicks the heating on. This is an adaptive system designed to maintain balance, and your metabolism is exactly the same.
The trick to sustainable weight loss is to reduce the calories to initiate fat burning, but to maintain a higher metabolism as much as possible. Giant deficits in calories results in muscle tissue breakdown, and metabolic hormone disruption. Ultimately this can result in poor energy and mood, poor sleep, low sex drive and very often, weight regain.
Enough of the doom and gloom of large calorie deficits – let’s get into how many calories you need to lose weight successfully. I do suggest however, reading the following posts to learn more about metabolic adaptation. It’s the missing piece that I feel leads people down the path of frustration and failure.
Please Stop Crash Dieting
How much weight can I lose in a month?
Calculating the numbers
So to lose weight we need to learn how many calories you expend in a day, just doing what you do. This is your total daily energy energy expenditure (TDEE). Keep in mind that this is never a fixed number, it’s always changing, and it’ll especially go down when you start to lose weight.
You can get a rough estimate of your TDEE using an online calculator, however these calculators are very inaccurate. If you were to stand in a room and look around you at the faces of all the people around you, consider just how different each person looks. So why wouldn’t it be any different for the way our energy systems work within us? Here’s the best TDEE calculator that i’ve come across online – NIH body weight planner, but I strongly recommend taking the time to figure out your TDEE manually.
Manually calculating TDEE (maintenance calories)
From now on, we’ll call your TDEE “Maintenance Calories”. It’s the amount of food you would eat to maintain the same weight. This means you’re eating the same amount of calories as you’re expending in a day.
Calculating maintenance calories requires tracking your food intake. It means for the next 7-10 days (10 is better), using an app like myfitnesspal, record everything you eat and record the data. Note that you are not trying to restrict yourself, you’re eating normally, and collecting baseline data.
In parallel, we need baseline data of your weight. Weigh yourself every morning at the same time after a toilet stop and record what it says. It will fluctuate every day as much as 1-1.5kg, so don’t stress the result. It’s just data.
Using the 7 days of calorie intake, take an average. Do the same with the weight. This is what we’re hoping to learn:
- If your weight didn’t change at all (+/- .5kg), you’ve found your maintenance calories. Eat like this every day & you’ll theoretically stay the same.
- If it went up by more than 0.5kg, you’ve eaten more than your maintenance calories. Eat like this every day & you’ll theoretically continue to gain weight.
- If it went down by more than 0.5kg, you’ve eaten less than your maintenance calories. Eat like this every day & you’ll theoretically continue to lose weight.
What if weight did change? What now?
If your weight went up or down, we need to make further calculations. Don’t worry it’s pretty straight forward. Let’s demonstrate this with an example. We’ll stick with kg for this calculation.
Mrs X accumulated her data over 7 days. She calculated her averages and this is what she got – 2800cal consumed with a 0.7kg gain. Let’s figure out roughly how much this 0.7kg equates to in calories.
- 1kg of weight gain/loss = 7,700 calories (estimated).
- 7,700 x 0.7kg = 5390. Mrs X ate 5390 too many calories in that week.
- 5,390 / 7 days = 770 per day
- Subtract 770 from 2800 = 2030.
Mrs X has calculated her maintenance calories to be roughly 2030 calories. From here she can decide how much to reduce her calories for the desired result. If she were to go for a 15% reduction in calories for a sustainable weight loss she’d get this:
- 2030 x .15 = 305 (round to 300)
- 2030 – 300 = 1730. (Why not round it to 1700)
Mrs X will now focus her daily intake around 1700 calories per day. She’ll likely expect to lose around .330kg per week. This is a very healthy and sustainable weight loss goal.
Important Considerations when calculating calorie goals
Although the “eat less, move more” approach is indeed the foundation of weight loss, there are some considerations to take into account. The common assumption that one could make is: the more weight I hope to lose, the more i’ll create a larger calorie deficit. Many calorie tracking apps are actually set up like this – It asks your age, height, weight & activity level. Asks you how much weight you want to lose and by when. Then it spits out a number for you. Because we all want our results yesterday, it often spits out a calorie goal much too low to be sustainable…and often the reason why we regain weight.
When using your calorie tracker, use it to track your food intake and that’s it. Do not listen to its calorie or macro breakdown suggestions. These numbers are arbitrary.
The point of this post is not to go into detail about metabolic adaptation, but it’d be remiss of me not to point out this important consideration. One of reasons why so many people regain weight after dieting is because the calorie goal was too ambitious. The deficit was too large too soon, and the body fought it.
Metabolic adaptation is a fascinating concept that we’re just discovering in the weight loss world. As energy intake goes right down our brain recognizes this as a starvation threat. Naturally, in order to protect itself, basal metabolic rate (your maintenance calories) is throttled right down. The calorie deficit once created becomes much narrower, and in some cases negligible, so to prevent further weight loss. The classic plateau.
What’s thought to be the biggest cause for weight regain is the “diet after the diet”. Many people lose weight for an event or season, and once that event rolls around, it’s all fun and games. The food and booze fest that ensues, coupled with a lowered metabolism creates a large calorie surplus, which as one would expect, gets stored once again as fat. To understand this more, read the article Please Stop Crash Dieting. You’ll learn also how your body fight even harder to prevent you from losing fat again in the future. There’s a reason why people who diet the most frequently, find it harder with every attempt.
After reading this post, and other weight loss Q&A posts, you’re probably coming to understand more how individual weight loss is. Calories in calories out matters. How many calories to consume, and the amount of deficit really depends on who YOU are. What are your goals, what kind of lifestyle do you live, and what kind of dieting have you done in the past? And of course what is your current daily energy expenditure. Only once you know how much fuel your body uses to run, can you decide how many calories you’ll need to consume.