We don’t talk a lot about weight loss here at Lifehacker, mostly because weight loss is a thing that our culture talks far too much about. Pay attention to it a little too long, and you’re on a slippery slope of “thinner is better” and thinking of food and exercise only in terms of how they can make your body smaller.
Put another way, I hate when publications put their “health” and “fitness” content behind a weight loss lens, as there’s so much more to those areas of life. Food is both fuel and enjoyment; exercise can make us healthier and can also make us better at sports or better at the things we want to do in everyday life. That’s all true no matter your body size.
But you can lose weight if you really want to. Maybe a health professional has recommended that you do, or maybe you have your own reasons. (As a meathead, my reasons are usually “lose a little of the fat I gained in my latest bulk, so I can get back to putting on muscle.”) That said, if you feel like you’re always trying to lose weight, the National Eating Disorders Association has a helpline and a ton of online resources to help you out. Your mental health is more important than the size of your body.
So I’m not going to try to convince you that you should lose weight, nor am I going to assume that everyone wants to. But today I am going to share with you the basic facts of how weight loss works, so that you’re getting this as neutral information and not part of a sales pitch for a new fad diet.
The difference between losing weight and losing fat
When people talk about “losing weight,” they almost always want to lose fat, specifically.
Your body contains different tissues. Fat is one; muscle is another. Then you have your bones and organs, and throughout all these tissues you have water. (Water is a good and normal component: If you could fully dry out a human body, you would have jerky.)
People in the fitness world like to talk about body fat percentage. The lower it is, the less fat you have on your body. And the less fat you have—the “leaner” you are, in this jargon—the more visible the shapes of your muscles. If you want to be “toned,” that means you want some muscle, but also to be lean enough to see some of it.
It’s not worthwhile to worry about exactly what your body fat percentage is, nor try to measure your amount of muscle, because the scales meant to measure this are often very, very wrong. There are more accurate means—in some states you can ask for a medical-grade DEXA scan just for funsies—but even these have their error bars, and in truth it doesn’t matter. You can’t do anything useful with those numbers.
A basic scale, on the other hand, gives you a single number (your weight) that masks all that complexity. It’s a useful tool, but make sure you aren’t only chasing the number on the scale. If you lose a ton of weight, you might be losing muscle along with the fat, and that will leave you disappointed in the end. Muscle mass is important for health, to say the least.
So let’s go over the basics of changing your weight.
When you gain weight, you gain fat and maybe muscle
If you’re resistance training (for example, lifting weights) on a regular basis, your body wants to build muscle. If you eat enough protein to support your training, you’ll get slightly bigger muscles. It’s not easy to gain much muscle mass, at least once you’re past your beginner stage.
If you’re not resistance training, weight gained is usually mostly fat.
When you lose weight, you lose fat and muscle
When you don’t eat enough food, your body uses its own tissues to fuel you. Some of that is fat, and this is what you’re aiming for when you say you want to “lose weight.” The trouble is that muscle often gets lost along with it.
The other important factor is that you’ll retain the most muscle when you lose weight slowly. That might be a pound a week or, for a smaller person, maybe only half a pound a week. On the bright side, a slow diet tends to be easy to stick with, since you’re eating almost as much food as usual.
Can you lose fat without losing weight?
Yes, with some caveats. If you resistance train and you eat a good amount of protein, your body will gain or retain muscle. It’s possible to stay at the same weight while gaining muscle and losing fat (sometimes called a “recomp,” as in body recomposition).
The catch is that building muscle and losing fat are asymmetric processes. It’s not that hard to lose a pound of fat: just eat 500 fewer calories each day for a week. It’s hard as hell to gain a pound of muscle; a person my size (I’m a smallish woman) probably can’t expect to gain more than five pounds of muscle per year. If you refuse to eat in a calorie surplus—in other words, if you refuse to gain weight in the process—that muscle gain progress will be even slower.
Recomp happens to a lot of us (especially people who are new to exercising) by accident. You don’t gain or lose weight, but after a year you look back at an old photo of yourself and you’re like: huh. If you don’t have specific weight goals, you can go ahead and just let this happen. But if you’re looking for quicker or more dramatic changes to your physique, it makes more sense to decide if you want to lose or gain weight, and eat accordingly.
So let’s talk about how you lose weight (with a goal of losing fat). If you want to gain weight, you can reverse the instructions, maintaining a calorie surplus instead of a deficit. And if you don’t care to change your bodyweight at all, you can stop reading here.
Alright, here’s the only thing you really need to know: You lose weight when you eat fewer calories than you burn.
Yes, there’s been a lot of debate over whether “a calorie is a calorie” or whether certain foods or diets are better than others for weight loss. But these differing opinions are all about how to achieve a calorie deficit, not about whether you need to.
The simplest approach is just to count the calories you eat (by using a food tracking app, usually) and to estimate what you burn. Simple and effective.
Another way is to subscribe to a specific diet ideology: One that says you should eat so little carbohydrate that you put yourself into (the harmless kind of) ketosis, or one that puts sugar and beans (yes, beans) entirely off-limits, or one that has you only eating during certain hours of the day. The end result is the same: You eat less food. (You don’t have to count calories to be eating less.)
Every one of these diets will try to tell you that it is the only or the best way to lose weight, but in truth there is no such thing as a “best” diet. Do whatever works for you, and be aware that some of the really restrictive diets may be detrimental to your mental health. Don’t ever feel that you have to stick to a particular diet framework to lose weight; none of them have any magic secret whatsoever.
In theory, this is simple: You find out how much you’re burning, and then eat less than that. Only problem is, you will never know exactly how many calories you burn, and you have to be at peace with that fact.
Here’s what you need to do:
- Come up with a starting guess of how many calories you burn per day.
- Eat slightly less than that amount.
- See if your weight changes.
For that starting guess, the most accurate way is to track what you eat during a period of a few weeks when your weight is not changing. (We recommend an app called Cronometer for tracking.) The average number of calories that you ate per day during that time can be considered your weight-maintenance calories.
But you’re in a rush. We all are, for some reason. Look up a TDEE calculator (not BMR or RMR) like this one. TDEE stands for “total daily energy expenditure” and it includes everything your body does during the day, including exercise.
No calculator is going to be totally accurate, but this one seems to work pretty well. It’s got me spot-on at about 2,300; I know that with my current exercise schedule I gain weight if I eat 2,800 and I lose weight at 2,000. (It also comes highly recommended by several fitness forums. This doesn’t guarantee accuracy, but remember, we’re looking for a very rough starting estimate.)
From there, subtract a few. A “healthy” rate of weight loss is often considered to be one to two pounds per week maximum, according to sources like the CDC. If you’re a bigger person with more to lose, you’d be on the higher end. Even so, I would go more conservative, especially at first. Subtracting 500 calories from your daily intake will lose you about a pound a week, in theory. A deficit of 250 calories will be more like half a pound a week. Even though a faster rate of loss will get you to a lighter weight sooner, a slower rate will be a lot easier to deal with: Less hunger, more room to enjoy desserts and snacks and restaurant meals and cocktails and all the other things you enjoy.
Keep tabs on whether you’re losing weight at the rate you expect. After a while, the weight loss will slow down, and that’s normal. Research shows that even though a pound of fat is “worth” about 3,500 calories (hence the 500-a-day deficit), by the time you’re deep into a diet, you need to burn what seems like 7,000 calories to lose each pound of fat. (Thermodynamics hasn’t been violated; your body just gets really good at conserving energy, throwing off your calculations.)
Okay, you’re thinking, but what about burning calories with exercise? Here’s the thing: It’s overrated.
You should still exercise, of course, but I would recommend that you not worry about exactly how many calories your exercise is burning.
Cardio is important for your health for many reasons. It reduces your risk of cardiovascular disease and other chronic health conditions; it also makes you more able to do everyday activities (walking, yard work, whatever) without feeling so tired. And strength training is important as well: You’ll retain more muscle mass, and you’ll be at lower risk of random injuries and aches and pains. You should do both strength training and cardio whether you’re trying to lose weight or not.
But the calories you burn? Ignore those numbers. First of all, those were included in your TDEE, back when you selected whether you do “light exercise” or whatever. Second, calorie counts on gym equipment and from activity trackers are rarely anywhere close to accurate.
And third, remember how your body is really good at conserving energy? Exercise just doesn’t always burn as many calories as it’s supposed to. You might spend more time loafing on the couch after you do a HIIT workout, or in some cases your body might save energy from obscure bodily functions (the research on this stuff has found things like changes in the energy expenditure of your internal organs.) You’re just a sack of meat, standing in front of a bathroom scale. You don’t need to get into the details.
To be clear, exercise does burn calories, even if we can never be sure exactly how many. A lot of us find that the more exercise we do, the easier it is to lose weight without being miserable. If I never exercised, I’d have a TDEE of around 1,600 calories and I’d need to eat something like 1,200 to lose weight. (That’s, like, a single Chipotle burrito.) But as a highly active person, I burn significantly more than that, and I can lose weight while eating 2,000. The 2,000 calorie life is vastly more enjoyable, and healthier in the long run, than the 1,200 calorie life.
The difference between a diet and a lifestyle change
Every diet these days likes to say that it’s not a diet. This is, of course, bullshit. If you’re eating to lose weight, you are dieting. You might do this at the same time as adopting healthier habits like eating more vegetables and getting more exercise. Great! But a “lifestyle change” implies that you’ll be doing the same thing for the rest of your life and getting the same results. You can’t lose weight forever, and you wouldn’t want to.
It’s better to think of losing weight as something you do for a set amount of time, and then you stop. Rather than setting a goal weight and doing anything in your power to reach it, set a timeframe—maybe two months—and see what happens when you follow a reasonable calorie deficit in those two months. Take a break to eat at maintenance. Then decide if you still want to lose weight, or if you’re done.
This way, you won’t be dieting forever, and you won’t be tempted to follow a crash diet to drop X pounds in Y weeks. Drinking nothing but spicy lemonade or expensive juice (or whatever the latest “detox” is) just isn’t worth your time.