There are many things people believe about weight loss that aren't true. In fact, many things taught by people who call themselves experts aren't true.

These myths, misunderstandings and falsehoods will hold you back unless you understand the facts.

Let's go through some of them below...

MYTH: Calories In Calories Out doesn't work; "a calorie is NOT a calorie"

Reality: People love to talk about how calories aren't equal and how it is only the type of food you eat that matters. The reality is that a calorie is a unit of energy and cannot simply disappear (see Energy Balance Principle). However, it is true our body reacts biologically and psychologically to different nutrients in different ways, and that can have a big effect on how easy it is to lose weight. So what people are really trying to say is that "calorie quality" matters.

The reality is to lose weight you need to keep in mind both principles: "Energy in / Energy Out" AND "Calorie Quality". So, yes, focus on calorie quality (see Fat Burning Foods) but you also have to realize that ultimately, a calorie deficit is ALWAYS required to lose fat, regardless of what you eat.

Too many people get frustrated when they start believing the diet type alone is the magic (paleo, keto, low-carb, mediterranean, zone, you name it) and then become baffled or frustrated if/when weight loss stops or doesn't happen. Your body can only shed fat if there is an energy deficit, meaning your body is forced to burn stored energy because energy coming in from what you're eating is not enough. It's just that some diet types are better suited to that goal.

The good news is that fully embracing the energy-balance principle or calories in/out will empower you and give you more flexibility than ever before. If you consume fewer calories than your body burns you really can eat "anything you want" without gaining weight if you don't exceed your calorie burn. This is especially true once you have reached your goal weight. If you are actively trying to lose weight, then calorie quality (the type of food you eat) matters a lot more.

MYTH: Only calories matter

Reality: Only partially true. See the above explanation.

MYTH: Only eating certain kinds of foods or a certain kind of diet matters

Reality: Only partially true. See the above explanation.

MYTH: It's all about carbs (aka, "carbs make you fat")

Reality: Carbs don't make you fat. Eating too many calories makes you fat. See Energy Balance Principle and Losing and Gaining. However, you do have to consider carbohydrate intake as part of the Calorie Quality principle. For most people, managing carb intake is a key part of a good weight loss strategy because it helps control eating. Read the Carb Smart Plan.

MYTH: "This" diet is better than "that" diet.

Reality: There's no such thing as a perfect diet or the "best" diet. You will react differently both biologically and psychologically to a specific diet than someone else, not to mention that we all have very different preferences, likes and dislikes. The only absolute requirement for losing weight is that you consume less calories than you burn, and that it's a diet you can stick with long enough reach your goals. Likewise, the only requirement for a diet that helps you maintain your current weight is one where you are caloric balance (calorie intake equals calorie burn), and is one you can stick with for the long term. Again, refer to the Energy Balance Principle and Losing and Gaining.

MYTH: Rapid weight loss diets are bad or will cause rebound weight gain

Reality: False. The idea that losing weight quickly is unhealthy or will cause you to gain weight back quickly has no proven scientific basis. The truth is, losing quickly is very motivational for most people, and many studies prove that losing more quickly in the beginning makes it more likely you will keep the weight off long term. The reality is that a rapid weight loss plan can be a part of a successful overall strategy, depending on the individual. However, a good weight maintenance plan after a quick-loss diet is necessary to keep the weight off. See Fast or Slow for a complete discussion.

MYTH: "Starvation mode" must be avoided

Reality: The way people use the term is a myth. The only true starvation is when all fat reserves have been used up and the body is forced to use protein from organs and other tissues. In a starvation situation, such as fasting or very low calories, if you still have fat stores to lose (extraneous fat on your body) true starvation mode won't happen to you. Your body is smart enough to burn fat stores before vital organs. That's why the body has fat stores in the first place. However, note that when scientists study weight loss, they sometimes use the term "starvation" to mean total calorie restriction, like fasting, but it's not unhealthy. Also, your body does in fact go through some metabolic adaptations in response to fat loss (see Metabolic Adjustments) that some people refer to as 'starvation mode' but again that's a misleading label because metabolic adaptations are a natural response and not something you can avoid unless you choose to not lose weight at all. However there are strategies for dealing with the metabolic adjustments that hinder weight loss (see Diet Vacations (Take Breaks)).

MYTH: My metabolism is ruined because of dieting

Reality: False. Dieting cannot ruin or damage your metabolism... even if you've had years of yo-yo dieting... even if you've gotten to super low fat levels on an extreme diet. It's true that your body may try to fight back and will adjust your metabolism as weight is lost. And there may be some evidence of body weight set points. And age-related factors play a part in weight loss problems. But you don't need to worry about permanently wrecking your metabolism. Whatever your past history of weight loss, it hasn't caused permanent harm and your chances of success remain the same. What is most harmful is not trying to control your weight at all!

MYTH: Help! I gained X pounds overnight!

Reality: You may have gained water weight but you haven't gained fat. A pound of fat contains 3500 calories. And to gain fat, you have to actually eat fat itself because it is very unusual for carbs or protein to be converted to fat. So ... did you eat 3,500 or more calories of actual fat yesterday, above and beyond your weight maintenance-level calories? No?... then you didn't gain X pounds of true weight (fat). However, there are number of reasons your weight could suddenly spike from water weight; the most common is carb storage in the form of glycogen (but it's NOT fat). The bottom line is that true fat gain occurs over a longer period of time, not in a day. See Real Weight vs Water Weight for more on this topic.

MYTH: Weight loss supplements are [worthless] or [a miracle]

Reality: Supplements are not worthless, nor are they miracle pills. The fact is they can be extremely helpful to certain people undergoing a weight loss program when taken for specific reasons and you examine proper evidence. There are a number of reasons why you might want to use supplements. Just have the proper expectations and use them intelligently. See Truth About Supplements in our Supplements Guide.

MYTH: What author X or scientific study Y says is the absolute truth I should follow.

Reality: Experts and scientific evidence are great resources and can help guide you in the right direction, but you can't ignore your own personal results. You should obtain the best instruction, but then realize it's all just a personal experiment, where you are the ultimate judge. You will always know more about yourself than anyone else. Remember that not everything you try will work, so don't build all your hopes on one thing. See Individuality.

MYTH: "Always listen to your body".

Reality: Most of the time that is true. You should be able to recognize when something just isn't right. If you notice adverse effects, or aren't getting results you want, use common sense and stop or change what you're doing. On the other hand, some things about weight loss are difficult and/or require effort and some self-discipline. If you give up whenever your body complains about making changes, you won't make it very far! Starting an exercise routine is one of those areas (see the Physical Activity section). Handling hunger is another one — see Managing Hunger for tips. The bottom line is that you have to learn what's helping you and what's hurting you versus what's simply feeding your addictions, bad habits or our natural desire to avoid effort. Use your common sense and always consult with a doctor regarding your diet and exercise plans or concerns.

MYTH: "I'm doing everything right but I'm not losing weight!"

Reality: You might be doing all you know how to do, but if you are truly in a calorie deficit, it's impossible to not be losing some fat. It's common for your scale weight to stay the same while fat loss is continuing. This could occur for a number of reasons (see Real Weight vs Water Weight and Fat vs Muscle). You may be exercising too much compared to your energy intake, which is causing too much stress and slowing weight loss. Either way, the solution could very well be to take a break (see Diet Vacations). There is also a high likelihood that you are underestimating how much you are eating (see Under-Estimating Calories) which means you aren't actually in a calorie deficit at all. Or, if you are doing resistance exercise and consuming adequate protein, you may be gaining more muscle which weighs more (which is why it is often better to track inches lost). See Fat vs Muscle. One way or another there is a reason (and a solution) for stalled weight loss. Also see Troubleshooting.