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 Carbohydrates: How carbs fit into a healthy diet Carbohydrates aren't bad, but some may be healthier than others. See why carbs are important for your health and which ones to choose. By Mayo Clinic Staff 
 
 Carbohydrates often get a bad rap, especially when it comes to weight gain. But carbohydrates aren't all bad. Because of their numerous health benefits, carbohydrates have a rightful place in your diet. In fact, your body needs carbohydrates to function well. 
 
 But some carbohydrates might be better for you than others. Understand more about carbohydrates and how to choose healthy carbohydrates. 
 
 Understanding carbohydrates 
 
 Carbohydrates are a type of macronutrient found in many foods and beverages. Most carbohydrates occur naturally in plant-based foods, such as grains. Food manufacturers also add carbohydrates to processed foods in the form of starch or added sugar. 
 
 Common sources of naturally occurring carbohydrates include: 
 
 Fruits 
 
 Vegetables 
 
 Milk 
 
 Nuts 
 
 Grains 
 
 Seeds 
 
 Legumes 
 
 Types of carbohydrates 
 
 There are three main types of carbohydrates: 
 
 Sugar. Sugar is the simplest form of carbohydrate and occurs naturally in some foods, including fruits, vegetables, milk and milk products. Types of sugar include fruit sugar (fructose), table sugar (sucrose) and milk sugar (lactose). 
 
 Sugar is the simplest form of carbohydrate and occurs naturally in some foods, including fruits, vegetables, milk and milk products. Types of sugar include fruit sugar (fructose), table sugar (sucrose) and milk sugar (lactose). Starch. Starch is a complex carbohydrate, meaning it is made of many sugar units bonded together. Starch occurs naturally in vegetables, grains, and cooked dry beans and peas. 
 
 Starch is a complex carbohydrate, meaning it is made of many sugar units bonded together. Starch occurs naturally in vegetables, grains, and cooked dry beans and peas. Fiber. Fiber also is a complex carbohydrate. It occurs naturally in fruits, vegetables, whole grains, and cooked dry beans and peas. 
 
 More carbohydrate terms: Net carbs and glycemic index 
 
 Terms such as "low carb" or "net carbs" often appear on product labels. But the Food and Drug Administration doesn't regulate these terms, so there's no standard meaning. Typically "net carbs" is used to mean the amount of carbohydrates in a product excluding fiber, or excluding both fiber and sugar alcohols. 
 
 You probably have also heard talk about the glycemic index. The glycemic index classifies carbohydrate-containing foods according to their potential to raise your blood sugar level. 
 
 Weight-loss diets based on the glycemic index typically recommend limiting foods that are higher on the glycemic index. Foods with a relatively high glycemic index ranking include potatoes and white bread, and less healthy options such as snack foods and desserts that contain refined flours. 
 
 Many healthy foods, such as whole grains, legumes, vegetables, fruits and low-fat dairy products, are naturally lower on the glycemic index. 
 
 How many carbohydrates do you need? 
 
 The Dietary Guidelines for Americans recommends that carbohydrates make up 45 to 65 percent of your total daily calories. 
 
 So, if you get 2,000 calories a day, between 900 and 1,300 calories should be from carbohydrates. That translates to between 225 and 325 grams of carbohydrates a day. 
 
 You can find the carbohydrate content of packaged foods on the Nutrition Facts label. The label shows total carbohydrates — which includes starches, fiber, sugar alcohols, and naturally occurring and added sugars. The label might also list separately total fiber, soluble fiber and sugar. 
 
 Carbohydrates and your health 
 
 Despite their bad rap, carbohydrates are vital to your health for a number of reasons. 
 
 Providing energy 
 
 Carbohydrates are your body's main fuel source. During digestion, sugars and starches are broken down into simple sugars. They're then absorbed into your bloodstream, where they're known as blood sugar (blood glucose). 
 
 From there, glucose enters your body's cells with the help of insulin. Glucose is used by your body for energy, and fuels all of your activities — whether it's going for a jog or simply breathing. Extra glucose is stored in your liver, muscles and other cells for later use, or is converted to fat. 
 
 Protecting against disease 
 
 Some evidence suggests that whole grains and dietary fiber from whole foods help reduce your risk of cardiovascular diseases. Fiber may also protect against obesity and type 2 diabetes. Fiber is also essential for optimal digestive health. 
 
 Controlling weight 
 
 Evidence shows that eating plenty of fruit, vegetables and whole grains can help you control your weight. Their bulk and fiber content aids weight control by helping you feel full on fewer calories. Contrary to what low-carb diets claim, very few studies show that a diet rich in healthy carbohydrates leads to weight gain or obesity. 
 
 Choose your carbohydrates wisely 
 
 Carbohydrates are an essential part of a healthy diet, and provide many important nutrients. Still, not all carbs are created equal. 
 
 Here's how to make healthy carbohydrates work in a balanced diet: 
 
 Emphasize fiber-rich fruits and vegetables. Aim for whole fresh, frozen and canned fruits and vegetables without added sugar. Other options are fruit juices and dried fruits, which are concentrated sources of natural sugar and therefore have more calories. Whole fruits and vegetables also add fiber, water and bulk, which help you feel fuller on fewer calories. 
 
 Aim for whole fresh, frozen and canned fruits and vegetables without added sugar. Other options are fruit juices and dried fruits, which are concentrated sources of natural sugar and therefore have more calories. Whole fruits and vegetables also add fiber, water and bulk, which help you feel fuller on fewer calories. Choose whole grains. Whole grains are better sources than refined grains of fiber and other important nutrients, such as B vitamins. Refined grains go through a process that strips out parts of the grain — along with some of the nutrients and fiber. 
 
 Whole grains are better sources than refined grains of fiber and other important nutrients, such as B vitamins. Refined grains go through a process that strips out parts of the grain — along with some of the nutrients and fiber. Stick to low-fat dairy products. Milk, cheese, yogurt and other dairy products are good sources of calcium and protein, plus many other vitamins and minerals. Consider the low-fat versions, to help limit calories and saturated fat. And beware of dairy products that have added sugar. 
 
 Milk, cheese, yogurt and other dairy products are good sources of calcium and protein, plus many other vitamins and minerals. Consider the low-fat versions, to help limit calories and saturated fat. And beware of dairy products that have added sugar. Eat more legumes. Legumes — which include beans, peas and lentils — are among the most versatile and nutritious foods available. They are typically low in fat and high in folate, potassium, iron and magnesium, and they contain beneficial fats and fiber. Legumes are a good source of protein and can be a healthy substitute for meat, which has more saturated fat and cholesterol. 
 
 Legumes — which include beans, peas and lentils — are among the most versatile and nutritious foods available. They are typically low in fat and high in folate, potassium, iron and magnesium, and they contain beneficial fats and fiber. Legumes are a good source of protein and can be a healthy substitute for meat, which has more saturated fat and cholesterol. Limit added sugars. Added sugar probably isn't harmful in small amounts. But there's no health advantage to consuming any amount of added sugar. The Dietary Guidelines for Americans recommends that less than 10 percent of calories you consume every day come from added sugar. 
 
 So choose your carbohydrates wisely. Limit foods with added sugars and refined grains, such as sugary drinks, desserts and candy, which are packed with calories but low in nutrition. Instead, go for fruits, vegetables and whole grains. 
 
 
 
 

 Bacon became my new best friend on the ketogenic diet. Business Insider 
 
 A viral diet that's been found to burn up to 10 times as much fat as a standard diet is gaining momentum among Silicon Valley tech workers. And it involves eating a lot of fat. 
 
 The ketogenic, or "keto," diet — which first became popular in the 1920s as a treatment for epilepsy and diabetes— limits carbohydrates to no more than 50 grams a day, which is the rough equivalent of a plain bagel or a cup of white rice. By comparison, dietary guidelines from the US Department of Agriculture recommend from 225 to 325 grams of carbs a day. 
 
 On the keto diet, the body goes into starvation mode and taps its fat stores for fuel. Studies suggest the low-carb, high-fat diet may promote weight loss, improve focus, and stave off age-related diseases. More research is needed on its long-term effects, especially among healthy people. 
 
 A small study recently published in the journal Diabetes and Metabolic Syndrome found that adults who had been diagnosed with metabolic syndrome (a precursor of diabetes) and ate a ketogenic diet had resting metabolic rates (a measure of how much energy your body burns when at rest) more than 10 times as high as people who ate a standard diet. 
 
 Last year, I spent two months eating bacon, butter, and avocados to see why the keto movement is so popular with tech workers. Here's what it was like. 

 I am no stranger to diets. I've cut sugar, counted points on Weight Watchers, and swapped solid food for Soylent, a venture-capital-backed meal-replacement shake. I gave up breakfast for a week and drank this caffeinated meal-replacement shake instead » 
 
 But those usually don't last long. I love food. I'm a chronic snacker. 
 
 When I learned about the keto diet, it caught my interest because dieters could eat seemingly unlimited amounts of healthy fats, like cheese, nuts, avocado, eggs, butter — foods that have high "point values" on Weight Watchers and are severely restricted. The keto diet reorganizes the building blocks of the food pyramid. It cuts down carbs to 20 to 50 grams a day, depending on a person's medical history and insulin sensitivity. (There are about 30 grams in one apple or half of a plain bagel.) On the diet, healthy fats should be about 80% of a person's daily calories, while protein should be about 20%. On average, Americans get about 50% of their calories from carbs, 30% from fat, and 15% from protein, according to the Centers for Disease Control and Prevention. 
 
 The keto diet is like Atkins on steroids. It turns the body into a fat-burning machine. The human body breaks down carbohydrates into glucose, which is used for energy or stored as glycogen in liver and muscle tissue. But it has a plan-B fuel supply. When carbs go missing from a person's diet, the body uses up its glucose reserves and then breaks down stored fat into fatty acids, which, when they reach the liver, are converted into an organic substance called ketones. The brain and other organs feed on ketones in a process called ketosis, which gives the diet its name. Keto dieters eat lots of fat to maintain this state. While the low-carb diet dates back to the 1920s, when it was found to reduce seizures in people living with epilepsy, Dr. Robert Atkins popularized a version of it in the '60s and '70s. Like the keto diet, the Atkins diet restricts carb consumption to 20 to 25 grams a day during an introductory phase, but then ramps up to 80 to 100 grams a day. So it's less strict than keto. 
 
 But the keto diet is not for everyone, so I sought medical supervision. Dr. Priyanka Wali is an internal-medicine physician with specialty training in obesity medicine. She uses the keto diet routinely for her patients who have insulin resistance, pre-diabetes, and diabetes. In 2014, Wali was moonlighting at a weight-loss clinic in San Francisco, where she saw her patients struggle to stick to their strict diet programs and maintain their weight loss. She started reading studies on low-carb diets and became convinced it was the solution. Wali made herself a guinea pig before she prescribed the diet. And it worked. She said she "expected to feel a lot of adverse side effects" from eating so much fat, "but what ended up happening was I felt great." "I started to have more energy and concentration," Wali said. "I didn't lose weight, but my fat distribution changed, so I lost weight from my hips." 
 
 After asking me about my family history and my reasons for trying the keto diet, Wali determined I was an "optimizer," like the healthy tech workers who rely on the diet. Tech workers living in the Bay Area sometimes go to extreme lengths to improve their bodies and minds. For example, at the supplements startup HVMN (formerly known as Nootrobox), most employees don't eat on Tuesdays — a ritual they say improves ketone production and productivity. Intermittent fasting has been found to assist ketosis. To see whether I was a good fit for the keto diet, Wali requested I have some lab work done, including a cholesterol panel and a fasting-insulin-level test. My results came back normal, meaning there was no medical necessity for me to go on the diet. If I were pre-diabetic or insulin-resistant, Wali would likely have made the keto diet part of my treatment. 
 
 Wali introduced me to the "keto food pyramid," via this image that went viral on Reddit. We agreed that for my first week on the keto diet, I would aim for 30 to 50 grams of carbs during the day and eat regular, carb-heavy dinners, even if they took me over the limit. "Sugar addiction is a real thing," Wali told me in our first meeting. She wanted me to ease into ketosis to avoid "carbohydrate withdrawal," which can cause irritability, depression, headaches, lethargy, and nausea. I was happy to take it slow. As I was learning the carb loads of different foods in those first few weeks, I tracked my meals on the Fitbit and Weight Watchers apps, but Wali says paper and pen works just as well. 
 
 She taught me how to count carbs the smart way: Carbohydrates - dietary fiber = net carbs. Fiber is a carbohydrate that the body can't digest. It doesn't raise blood-sugar levels, so there's no use in counting grams of dietary fiber toward a daily carbohydrate goal. A cup of almonds has about 20 grams of carbohydrates, but 12 of those come from dietary fiber. As a result, I had to count only 8 grams for the serving. What a bargain! 
 
 Pasta was off the menu. A cup of cooked whole-wheat noodles has about 41 net carbs, which would blow through my daily carb allowance in one small portion. 
 
 I had to be careful even with fruits and starchy vegetables. A cup of blueberries has about 11.5 net carbs. It's also low in fiber, so it's not very filling for long. 
 
 When I got home from my visit with Wali, I was forced to rethink all my dietary staples. I let my boyfriend finish off our supply of apples, bananas, bread, pasta, rice, and potatoes. 
 
 And I said yes to fat. A typical breakfast included a coffee with half-and-half, along with cheesy eggs cooked in butter and two slices of bacon. Some mornings I scrambled to find 20 minutes to make breakfast. Few restaurants had dishes that met my dietary restrictions. I ate a sad, tortilla-less breakfast burrito once. I managed to find one restaurant, La Boulangerie in San Francisco, that makes scrambled eggs with mix-ins to order. I swapped potatoes for a side salad and tossed the toast. It cost $11. 
 
 For lunch, I ate a lot of "sad desk salads." Two cups of leafy greens, an ounce of cheddar cheese, a handful of nuts, and avocado or cauliflower rang up about 6 net carbs. 
 
 Our office has the best snacks — Goldfish, Nature Valley bars, animal crackers, and peanut-butter-filled pretzels (my personal brand of indulgence). I thought of them often. I used to snack every hour between 10 a.m. and dinner. Food was always on my mind. In my first week, I dug up the willpower to resist those sugar binges. But it was not without consequences. My headaches pounded for hours on end. My mind said, "Eat something." Wali recommended I drink more water and salt my food to ease the headaches. 
 
 I scoured keto blogs for high-fat snacks — called "fat bombs" — to power me through the sugar cravings. Loaded cauliflower made with butter, sour cream, cheddar cheese, and bacon became my go-to treat. The keto comfort food didn't make me feel deprived. Here's the recipe for loaded cauliflower » 
 
 During Week 2, my ketone-testing meter kit arrived in the mail. The pocket-sized medical device uses a small blood sample to measure the presence of ketones. A doctor can prescribe a ketone-testing meter to people with diabetes, but insurance may not cover it. Optimizers like me turn to Amazon for third-party sellers. I bought the Precision Xtra glucose-meter kit (which also measures ketones) for $22, and a 10-pack of ketone testing strips for $42. The meter has since gone up to about $60 on Amazon. Keto adherents use ketone-testing meters to check whether they're in a state of nutritional ketosis — generally considered to be above 0.3 millimoles per liter of blood, according to Wali. Entrepreneurs sometimes share their ketone levels on social media. It's the biohacking community's equivalent of posting photos of a bathroom scale to celebrate recent weight loss. 
 
 My first encounter with a lancing device, a tool that draws blood from the fingertip, was not particularly pleasant. Afterward, I held the ketone-testing meter to the drop of blood. 
 
 I got 0.4 mmol/L, a low-level state of nutritional ketosis. In less than two weeks on the diet, my body had flipped the switch from burning carbs to burning fat as its primary fuel source. 
 
 Three weeks in, I felt the difference. Even on days when I ate bun-less cheeseburgers for lunch, my energy was sky-high. I no longer needed coffee to stay awake in the afternoon. 
 
 I suddenly could go three, four, even five hours without thinking about food. My snacking became much less frequent, and I became more focused on work as a result. Dr. Jason Fung, who specializes in kidney care, offers an analogy in his book "The Obesity Code." Imagine sitting down to an all-you-can-eat buffet. At some point, the idea of eating one more pork chop becomes sickening. But if the dessert cart passes, it's hard to resist. That's because highly refined carb-filled foods, like cake and pie, don't trigger hormones in the brain that say: "You're full. Stop eating." Proteins and fat can signal when you've had enough. 
 
 When I splurged on a bagel or pizza, which did happen, I wanted to curl up under my desk and nap within 30 minutes of eating. I felt uncomfortably full and groggy. The worst part of cheating was that it had the potential to reverse a state of nutritional ketosis. When my parents came to town over one weekend and I went rogue, I wound up with a ketone reading of 0.3 mmol/L, meaning my body was burning more carbs than fat. I returned to the diet that Monday, but it takes an average of five days for the body to use up the leftover glycogen reserves and return to nutritional ketosis, Wali says. 
 
 To avoid the ill feelings that carbs gave me, I experimented more in the kitchen. I learned that pizza made with a baked cauliflower crust was not pizza. It tastes like a vegetable casserole, but at least I don't wake up feeling bloated. 
 
 Eating at restaurants was the hardest part. I ate taco fillings out of tortillas and scraped the breading off fried chicken. Every menu had just one or two things I could order guilt-free. 
 
 After eating mostly fat, protein, and leafy vegetables for one month, I reached my peak ketone reading of 0.9 mmol/L — a strong indication that I reached a state of ketosis. By this point in my journey, most of the negative side effects had subsided. (I experienced leg cramps and tingling sensations in my feet, which Wali said was from eating too little salt. She suggested I try magnesium supplements, and the problem went away within days.) A ketone reading of 0.9 mmol/L indicates a mild state of ketosis. Dieters can reach higher levels — "go deeper" into ketosis — by restricting carbs to fewer than 20 grams a day or fasting. But there isn't consensus in the medical community that doing so unlocks additional benefits. Geoff Woo, the cofounder and CEO of HVMN, said he aimed for 3.0 mmol/L or higher, which he achieves through intermittent fasts that spike ketone production, for "optimal mental flow." When I started to obsess over the numbers my ketone testing meter gave me, Wali encouraged me to instead focus on how I felt. 
 
 It was then that I realized why I loved eating keto — it made me feel like a superhero. When I lost 30 pounds on Weight Watchers in college, I celebrated the numbers on the scale and how my clothes fit. But because I continued to eat carbs in smaller portions, I was still prone to sugar crashes and afternoon "brain fog." The transformation was incomplete. The keto diet made over my mind and my body. The sense of mental clarity and energy that came on about three to four weeks into eating keto was unlike anything I've experienced. I woke up feeling strong, confident, and capable of taking on whatever the day threw at me. "This is how you're supposed to feel as a human being," Wali said during a follow-up visit.
– Silicon Valley techies adopt some unusual eating habits to boost productivity, including one firm where workers fast on Tuesdays. Melia Robinson wanted to see how one of these dieting regimens would affect her, and she concludes for Business Insider that it "vastly improved my life." The course she followed: the ketogenic, or keto, diet, which deprives the body of carbohydrates—just 50 grams a day instead of the recommended 225 to 325 grams daily—and sends it into "starvation mode." What it then burns instead: a person's fat stores, which are broken down into organic byproducts called ketones, which then become the body's main fuel supply. To keep the fat stores well stocked, that means individuals on this diet have to scarf down plenty of cheese, eggs, and avocados. Off the menu: pasta, bread, rice, and other carb-heavy foods, including some fruits. And so, under the direction of a doctor, Robinson followed a routine she calls "Atkins on steroids." That meant breakfasts of butter-fried eggs and greasy bacon, as well as lunches consisting of "sad desk salads." Robinson sated hunger pangs in between with "fat bomb" snacks (her favorite: cauliflower smothered in butter, sour cream, and cheese). After just two weeks, she says her body "flipped the switch" and started using up her body fat to replace the carbs it had previously burned. Then her energy spiked, she no longer needed coffee as an afternoon pick-me-up, and her obsession with snacking waned. One month in, Robinson reached a "state of ketosis," with few remaining side effects. She not only lost 8 pounds over two months, but she experienced better concentration and more energy. "It made me feel like a superhero," she writes. More on Robinson's eating experiment here.