Everything makes you fat! Gluten-free food is the key to eternal youth! You need to poop ten times a day or you’ll die! You’ll find tons of equally ridiculous health claims around the internet, and you’ll actually believe some of them. Today we’re taking a look at 10 common myths and uncovering the truth.


While we’ve learned a lot about health issues here at Lifehacker over the years, we can’t claim expertise on any particular subject. To help us get to the root of these myths, we solicited the help of three experts: Dr. Carly Stewart (medical expert at Money Crashers), Andy Bellatti (Las Vegas-based registered dietitian), and Dr. Spencer Nadolsky (medical editor at Examine.com). They all offer a unique perspective on each myth but mostly came to the same conclusions: we have a lot of silly misinformation out there about our health.

Myth 1: Eating Fatty Food Makes You Fat


It seems obvious that fat makes you fat, but what seems obvious often turns out to be wrong. After all, we used to believe geese grew on trees for reasons that actually made some sense. Just because fat goes into our body doesn’t mean it stays there, however, and so we’ve now found that a long-held assumption didn’t make a lot of sense. Dr. Stewart explains:

Eating fatty foods does not make you fat. Fat in moderation is a necessary part of any healthy and balanced diet. Putting on more weight in the form of fat is a result of energy imbalance. You will gain weight if you take in more calories than you burn. Fat is a concentrated source of calories, but it is not necessary to eliminate fat from your diet completely.

Bellatti agrees, providing a little context as to why we might look at fat as a problem:

Sheer lunacy. Whole-food fats (nuts, seeds, avocado) are satiating and help you feel fuller for a longer period of time. You can't put French fries and almonds in the same category simply because both are "high in fat.”


Foods like french fries don’t fill you up. They also don’t contain other useful nutrients like foods with good fats (like the ones Bellatti mentioned). Dr. Nadolsky also agrees that it really just comes down to excess intake of anything:

Fat can make you fat, but so can carbohydrates and (to a much lesser degree) protein; it just matters that you over-consume the source of calories. Granted some fats are seen as 'better' than others (such as coconut oil and fish oil relative to trans fats) which accounts for some variability in weight gain, but weight gain will occur when 'excess' is consumed (whatever that may be to your body).


So fat won’t make you fat, unless you eat too much of it. You know, like anything else. You have to beware of fat free, as well, as it often actually contains fat and adds quite a bit of sugar. When something gets eliminated, make sure to find out what filled the void.


Myth 2: Eating Carbs Makes You Fat


If eating fat won’t make you fat, carbohydrates must! Right? Carbs, the devil of our current decade, get cut from just about every new fad diet to promote super fast fat loss. Again, the truth comes down to striking a healthy balance. Dr. Nadolsky explains why a healthy amount of carbohydrates don’t really cause a problem:

While it is becoming more popular to blame carbohydrates as the cause of obesity, people don't realize that de novo lipogenesis (DNL; which converts sugars into fat) tends to be inefficient in human bodies. For carbs to make one fat, they would need to work in concert with a poor diet and lack of exercise which makes those latter two more readily blamed.


So how do you tell when carbs cause problems? Bellatti explains:

More over-simplified nonsense. Again, a Pop-Tart (carbohydrate-rich) and a pear (also carbohydrate-rich) are not the same thing. The problem is refined and highly processed carbohydrates, which can trigger cravings.


Dr. Stewart elaborates:

It is a good idea to limit the number of carbs you eat in the form of sugar because sugar is low in nutritional value and high in calories. However, if you eliminate carbs completely, you will miss out on healthy food such as whole grain breads and wheat pastas. You will only gain weight if you consume more calories than you burn.


Perhaps you're seeing a pattern here: a healthy diet comes down to balance and choosing natural sources of carbs when you include them. You don’t have to eliminate them entirely, but focus on the options with greater nutritional value and limited processing.

Myth 3: MSG Is Bad For You


Monosodium glutamate, or MSG, has a sordid past. Many Americans look at MSG as anything from a dietary problem to a silent killer. In reality, if MSG poses a problem it doesn’t stem from the flavor enhancer itself, but where you tend to find it. Bellatti explains:

Yes and no. Some people don't respond to it well. My main thing with MSG is that it's a marker for highly processed foods.


Dr. Nadolsky also explains that most of our information about MSG doesn’t really add up to much:

MSG is commonly demonized as giving people headaches, and it's possible that some people are more sensitive to MSG or currently unknown reasons; these people can avoid MSG and treat it like some manner of allergen, but this doesn't mean that it is inherently bad (we don't know). MSG is often cited as causing obesity, but that is induced in mice with direct injections into the brain and 'supported' by binges at Chinese food establishments.


So should you avoid it? Sure, if it bothers you. Small amounts, however, shouldn’t have an impact on most people so don’t let it throw you into a panic.

Myth 4: High-Fructose Corn Syrup Is Worse Than Sugar


High-fructose corn syrup (HFCS) gets a bad rap. Make no mistake—it’s bad, but compared to sugar you won’t find a huge difference in the overall impact to your health. Dr. Nadolsky explains:

The content of fructose in both options (sucrose and HFCS) are pretty much similar, and if you ate enough HFCS for the extra 5% to matter then you over-consumed any type of sugar. There are no other known differences between these two sugars, and that one Princeton study saying otherwise has not only failed to have been replicated but is more than likely just misleading data.


Bellatti agrees, but adds that it has other negative impacts:

It's technically no different, but it's ubiquitous, takes a huge toll on the environment, and is a marker for highly processed foods.


As you may have noticed so far, a lot of stuff we consider problematic in our diets doesn’t cause as much trouble as we believe on its own but rather has a negative impact due to where you’ll find it. HFCS, carbohydrates, and fat often appear in highly processed foods. We think of them as bad because they exist in many unhealthy meal options and show up places where they don't necessarily belong. Rather than demonize an ingredient, we need to focus on the food as a whole. You won’t find much good stuff in HFCS or sugar, but you’re more likely to find sugar in nutritious options and HFCS injected into foods that don't need it.

For more on what sugar does to your brain and body, check out our explainer.


Myth 5: Gluten-Free Foods Are Healthier


The gluten-free craze recently took hold and you’ll find tons of options as a result. Will you benefit from eating them? That depends on what your specific body needs. Just because some people need to eat gluten-free doesn’t mean it will work for you. Bellatti explains when you need to rid it from your system and when it’s fine:

If you are celiac or gluten sensitive, gluten is problematic. Otherwise, the body is technically able to process gluten. The absence of gluten in a food does not automatically make it healthier (soda is gluten-free). A lot of gluten-free breads are made with refined starches, which are not healthful. While I think many people can tolerate gluten just fine, I also don't get concerned if someone tells me they feel better when they don't eat it. Shunning gluten from your diet doesn't put you at any sort of nutritional risk.


Dr. Stewart, for the most part, agrees:

Gluten-free foods are only healthier for you if you are allergic to gluten. If you aren't, eating a gluten-free diet restricts the amount of fiber, vitamins, and minerals you are able to consume. A variety of foods that are high in whole grains (such as foods containing wheat, rye, or barley) also contain gluten, and these foods are an essential part of a healthy diet. Most people have no trouble digesting gluten.


Why don’t most people have difficulty digesting gluten? Dr. Nadolsky explains:

You just cannot eat enough grain lectin (ie. gluten) to damage this tissue appreciably unless you have some preexisting impairment in the regenerative capacity of the intestines, which would refer to celiacs and maybe those with 'sensitivities.' Otherwise, worry about gluten is overblown since the intestines are made to recover from these stressors.


Unsurprisingly, people get duped when they meet celiacs whose lives improved vastly by cutting out gluten. Naturally, since they can’t process the stuff, that would happen. Few of us suffer from celiacs disease, fortunately, so we can handle products with gluten. Like with everything else, however, eat it with balance in mind.

Myth 6: Everyone Needs to Poop Daily


Some talented, amazing people can poop twice a day. How do they process that much waste? It must be magic. If you don’t make a bowel movement daily, it can seem like a problem when you compare yourself to those who take more frequent toilet breaks. Fortunately, you don’t have to worry. Everybody poops, but schedules vary. Dr. Stewart explains:

No single bowel movement schedule is right for everyone. However, staying hydrated, eating foods high in fiber, and being active will help ensure that your schedule is regular and you do not become backed up.


Dr. Nadolsky argues that regardless of how well you eat, you shouldn’t expect a predictable schedule:

The frequency of defecation is not something that should be put to a schedule, since it is a bit unreliable and dependent on food intake. Consistency of the stool, perhaps assessed by the bristol stool chart, is more reliable of an indicator of health than the frequency; while altering frequency does affect the body, it shouldn't be a major concern unless you get constipated or cannot function due to frequently watery defecations.


If you don’t poop frequently, don’t worry. Make sure your stool appears healthy and that it doesn’t cause you discomfort. Beyond that, you don’t need to worry much about your poop.

Myth 7: Microwaving Kills the Nutrients in Food


The microwave oven “nukes” your food, or so we’ve come to describe. Does it actually affect the nutrient content of your food, though? As Dr. Nadolsky explains, sort of:

Microwaving can kill some nutrients (sulforaphane from broccoli, for example) but this does not extend to all nutrients. Unfortunately, we need to look at this stuff on a case by case basis to see which foods you should microwave and which you cannot since there is no rhyme or reason to which compounds are damaged or inactivated. In general, microwaving is not a serious concern.


Even though the microwave won’t have a major impact on the nutritional quality of many foods, I think most of us can agree that it heats most meals unevenly and creates a disappointing texture. If you have any great reason to avoid the microwave, that’s probably a better one. Besides, cooking broccoli in any way can kill sulforaphane (or at least greatly slow its absorption into your body), so microwaves definitely do not have a monopoly on nutrient death.


Myth 8: You’ll Lose a Pound of Fat for Every 3,500 Calorie You Burn


We all want to believe a simple equation can lead us to fat loss. If we only need to burn calories to lose weight, in theory we should be able to track our progress through meticulous counting. Those who enjoy the predictability of numbers love this myth because it reduces weight loss to an accountable formula. Unfortunately, it’s not one you can actually count on because the science behind the equation lacks the consistency it sells. Dr. Nadolsky explains:

Technically you do lose a pound for every 3,500 calories, and we could calculate this if our methods for calculating energy expenditure and intake were perfect. Unfortunately we do not have perfect equations right now, so while a pound of fat does have about 3,500kcal in it we tend to lose a pound of fat when our diets give us somewhere between a 2,000 and 5,000 caloric deficit (because we calculated something wrong).


Why does it vary? As Dr. Stewart explains, burning a pound doesn’t necessarily mean it all comes from fat:

This statement is partially true. You do lose one pound for every 3500 calories burned (generally speaking), but that loss isn't actually all fat. It's a combination of fat plus a modest amount of water and other forms of tissue.


So while you can somewhat count on this equation to predict weight loss, if you have fat reduction as a goal you might wind up disappointed.

Myth 9: Spot Training Helps You Burn Fat in Specific Areas


Some people believe that focusing exercise to certain muscle groups and parts of the body can help burn fat in those areas. In a way this seems logical, as you’d think literally targeting your efforts on specific areas of your body would help disrupt the fat content. Unfortunately, fat loss doesn’t work that way. Dr. Stewart explains:

Doing sit-ups (or another type of spot training) will strengthen the abdominal muscles, but will not burn fat specific to that area. Fat is burned or lost throughout the body on a more even basis, and is accomplished through aerobic or cardiovascular exercise. The pattern of fat gain or loss has more to do with each person’s unique body than it does with the type of aerobic exercise performed.


The claim comes from somewhere, of course, and Dr. Nadolsky points out you really have to make a stretch to believe this claim:

Even if we get the most cherry picked evidence for this claim, the localized fat loss is pretty much one gram (for comparison, a can of coke has 40 grams of sugar). Fat loss comes from all over your body, and there is a lot of evidence that fat gets re-distributed even after localized fat loss surgery. With that said, men and women each tend to have stubborn areas (waist and hips/thighs respectively), and they are usually the last deposits of fat to go.


That doesn’t mean you shouldn’t perform focused exercises. Like with any healthy diet, it helps to have variety in your exercise regimen. While you should focus on your specific goals, don’t shy away from strengthening your muscles solely because it won’t burn the fat faster. For greater physical capability and aesthetics, you need a balance of different exercises that train your entire body.

Myth 10: The Scale Is a Good Way to Help You Manage Your Fat Loss Progress


When you diet and exercise, you want numeric proof that your efforts actually matter. Traditionally, we’ve stepped on the scale to see our weight decrease and considered that progress. For a variety of reasons, your weight will mislead you. You 're made of a lot more than just fat—water especially—so losing a pound can mean progress or it can mean nothing at all. Dr. Stewart explains:

Using the scale is not the best way to track the progress of a healthy diet and exercise. The scale treats both fat and muscle the same way – a pound of fat is the same as a pound of muscle. If you're strengthening your muscles during your exercise regimen, you might actually see a small amount of weight gain rather than weight loss, which is not a bad thing. A better way to track the progress of diet and exercise is to monitor how you feel and how you look. Your local fitness center may also be able to help with measuring your percent body fat.


If you want to learn more about effective tracking methods, read our guide.


Remember: We Still Don’t Know Everything

We still don’t know a lot about our health. Science often makes new discoveries and we learn a bit more, but we also run into several instances where new studies can get taken out of context by the news and myths—much like the ones in these posts. That said, you can only go on the best information currently available (that’s why we consulted doctors and a dietician for this post). Before you start worrying too much about what you eat or how you take care of yourself due to something you’ve heard or read, make sure you do the research and consult professionals. Often times the myths that propagate throughout our society take hold because they seem logical and reasonable, but science doesn’t back them up. Hopefully we’ve dispelled some good ones for you here today, but you’ll always find more. Remember to always keep learning, and that few health answers are definitive at this time.


A special thanks goes out to Dr. Carly Stewart, Andy Bellatti, and Dr. Nadolsky for their contributions to this post.


Dr. Carly Stewart is the medical expert at Money Crashers.

Andy Bellatti is a Las Vegas-based registered dietitian and you can check out his blog, Small Bites, to read more.


Dr. Spencer Nadolsky is the medical editor at Examine.com. Established in early 2011, it is an independent compendium on supplementation and nutrition, with over 25,000 citations.

Photo by IainBuchanan , Dominik Schwind , Nina Hale , John Fischer , Tony Alter , Orin Zebest , gleam_df , The U.S. Army , davidd , Igor Zh (Shutterstock), and Leremy (Shutterstock) .