--- title: Fasting Can Cause Weight Gain and Poor Sleep description: Given my 15-plus years in private practice I don’t believe there’s a one-size-fits-all approach to nutrition and weight loss. What works for one person may... canonical: https://time.com/3092085/weight-gain-and-3-other-reasons-why-fasting-is-bad-for-you/ author: TIME article:opinion: false article:content_tier: free article:published_time: 2014-08-09T14:00:22.000Z article:modified_time: 2026-08-04T08:00:55.402Z article:section: Health og:title: Fasting Can Cause Weight Gain and Poor Sleep og:description: Given my 15-plus years in private practice I don’t believe there’s a one-size-fits-all approach to nutrition and weight loss. 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Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators. ### Sources * TIME Newsletters: [time.com/newsletters](/c/time-nl-health-2026q3/newsletters?i=1432b333-5aaf-45dc-8b79-d8c9c41ce5ad&cr=time-nl-health-2026q3-v1) ## Video: The Truth About Fat [Watch (HLS stream): The Truth About Fat](https://cdn.jwplayer.com/manifests/uYGhfNfS.m3u8) (5:15)  _Published 2014-06-12. When you want to lose weight or get healthy, what is the first thing you would normally cut from your diet? If you said fat, you're not alone_ by [Cynthia Sass, MPH, RD](https://time.com/author/cynthia-sass-mph-rd/) ## Cynthia Sass, MPH, RD Aug 9, 2014 2:00 PM UTC by [Cynthia Sass, MPH, RD](https://time.com/author/cynthia-sass-mph-rd/) ## Cynthia Sass, MPH, RD Aug 9, 2014 2:00 PM UTC Given my 15-plus years in private practice I don’t believe there’s a one-size-fits-all approach to nutrition and weight loss. What works for one person may not work—or feel good—for another. That’s why I believe it’s so critical to listen to your body to determine what feels best and is sustainable for you, despite how popular an approach may be— from juice cleanses and detoxes to “caveman” versus vegan diets. Regarding one strategy that’s currently trending, intermittent fasting, I’ve seen very mixed results. Many men, particularly those who struggle with excess weight and conditions like diabetes or metabolic syndrome, have reported positive results with this semi-fasting approach. But for many women I’ve counseled, any type of fasting—whether it be overnight for 16 hours every night, or capping calories at 500 two days a week—has seriously backfired. If you’re thinking of giving it a try, here are four potential unwanted effects to consider. **Rebound overeating** Limiting food intake to just eight hours each day or severely restricting calories a few days a week are two popular fasting approaches. I’ve seen both lead to intense cravings, preoccupation with food, and rebound binge eating, particularly for women. Some who attempted to cut off eating after 4pm (with the intention of eating again at 8am) have told me that after hours of lingering thoughts about food, or watching other family members eat, they just couldn’t take it anymore, and wound up raiding the kitchen and eating far more than they would have on a typical night. Others, who attempt to eat no more than 500 calories a day two non-consecutive days each week, often begin daydreaming on fasting days about what they can eat on nonfasting days, and end up eating decadent goodies more often, like baked goods, pizza, chips, and ice cream. The lesson: even if this tactic has worked miracles for a friend, co-worker, or family member, if it leaves you in a food frenzy, it’s not the best approach for you. **Poor sleep** I’ve tried intermittent fasting myself, and like clients and others I’ve talked to, it interfered with my ability to fall asleep and stay asleep. This effect can not only wreak havoc with daytime energy, but a plethora of studies have shown that sleep length and quality are strongly associated with weight control. Too little sleep has been shown to increase hunger, up cravings for sweet and fatty foods, reduce the desire to eat healthy foods like veggies, and trigger excessive eating overall and weight gain. For these reasons, I don’t believe that fasting is an optimal strategy for many people. In fact, some clients have told me they got out of bed at 3am after waking up, and you guessed it, wound up either eating, drinking alcohol, or both, in order to fall asleep—not a good recipe for weight loss or wellness. **Fewer nutrients** As a nutritionist, one of my biggest pet peeves with fasting is that I’ve seen it compromise overall nutrition by limiting the intake of veggies, fruit, even lean protein and healthy fats, which are strongly tied to keeping metabolism revved, boosting satiety, and reducing inflammation—all critical for weight control. I think this is especially the case when people become focused on calorie counts rather than food quality. If you do decide to try intermittent fasting, or even a modified version, make every morsel count by sticking with naturally nutrient rich whole and fresh foods rather than processed “diet” products. **Muscle loss** Unfortunately, fasting doesn’t trigger your body to break down _only_ your fat reserves. While that would make weight loss so much easier, metabolism is a bit more complex. Your body burns a combination of fat and carbohydrate and after about six hours or so, when carbohydrates aren’t being consumed and your body’s “back up” stores in your liver have been depleted, you begin to convert some lean tissue into carbohydrate. The ratio of how much fat to muscle you lose may vary depending on your body composition, protein intake, and activity level, but again, this is where I’ve seen women and men experience different results. Research shows that in postmenopausal women, a higher protein intake is needed in order to lose less muscle mass (not offset the effect completely), but many women tell me that when they fast they crave carbs, which may lead to a loss of muscle while maintaining body fat—the opposite of their intended goal. Bottom line: again, think through what feels good and in sync with your body’s needs, and remember, sustainability is key. _More from Health.com_ [11 Foods That Make You Hungrier](http://www.health.com/health/gallery/0,,20835574,00.html) [14 Fad Diets You Shouldn’t Try](http://www.health.com/health/gallery/0,,20833428,00.html) [10 Bogus Health Trends That Waste Your Time](http://www.health.com/health/gallery/0,,20807139,00.html) This [article](http://news.health.com/2014/08/01/4-reasons-not-to-try-intermittent-fasting/) originally appeared on [Health.com](http://www.health.com/health/). Cynthia Sass, MPH, RD, _sports nutrition consultant_ to the NHL’s _New York Rangers_ and the MLB’s _Tampa Bay Rays._ ## Transcript [ MUSIC ] There's something we all enjoy about staying for dinner. You ever thought why? What was on your dinner table when you were younger? Chances are it had a lot to do with, what your doctor was telling you is healthy. Building a strong healthy body is like building a strong, beautiful building. If the foundation is weak, the whole building will be weak. It takes five fingers to point the way to healthful eating habits. Well, here we go. For years, the government published dietary guidelines. Meant to keep Americans healthy. There's a great deal to learn. Tell me what you eat, and I'll tell you what you are. The body needs certain substances to live and grow. And remember, your body isn't just like an automobile. For years, the key measures of those guidelines were the same, cut fat from your diet. The committee's original report urged Americans to reduce their risk of heart attack. By reducing their intake of cholesterol down to the equivalent of about one egg a day. And those guidelines had an effect. From 1977 to 2012, per capita consumption of eggs fell by 9 %, beef by 37 %, whole milk by 72 %. Calories from saturated fat fell, while calories from supposedly safe carbohydrates increased. As one expert put it, it was a vast nutritional experiment. With nearly a million American's a year dropping dead from heart disease in the mid 80s, we had to try something. Nearly four decades later results are in. The experiment was a failure. Americans are sicker than they've ever been before. The prevalence of diabetes has gone up 157 % from 1980 to 2011. Nearly one in ten Americans now has the disease. Causing the public health system $ 245 billion a year. Heart disease is still the number one killer in the country. Americans are as obese as ever. So, what went wrong? Good old granola. Great for taste but loaded with fat. It doesn't take much of imagine a leap to assume that fat would make us fat, clog our arteries and raise the risk of heart disease. It turns out that saturated fat is a lot more complicated than we think. Carbohydrates and fats are nutrients. Like man, you need nutrients to live and grow. [ MUSIC ] Firstly, there are two kinds of cholesterol. LDL which is linked to heart disease and HDL which can be protective. Fats that course through the blood are known as triglycerides and high levels of those are linked to heart disease. Saturated fat raises LDL cholesterol but also raises HDL. Moving LDL buildup on arterial walls. So raising both, makes saturated fat a cardio wash. One key piece of information is that LDL seems to come in two forms. Large and fluffy, small and dense. Those smaller particles are linked to heart disease, while the larger ones are mostly benign. Saturated fat increases the number of large particles. The opposite happens with carbs. I don't get it. Researchers have long since discovered the kind of fats found in olives and in fish like salmon. Are actually heart protective. Now it turns out the fats found in meat and dairy, aren't as bad as we feared before. So that means by focusing so much on fats. We may actually have been making ourselves sicker. So, she brings up the subject of reduced- fat cheese. It's a fat- free [ UNKNOWN ]. Fat- free, cholesterol free. Low- fat granola. Reduced- fat Kettle chips. Reduced- fat Chips Ahoy. Lowfat cottage cheese. Non- fat yogurt is the perfect example. The thinking for consumers was simple. Fat was dangerous. This product had no fat. Therefore, it must be healthy. It's non- fat, which means less calories. [ MUSIC ] But amid the confusion about fat, we end up replacing it in our diets with sugars and carbohydrates, which meant our calorie intake was actually going up. When carbs and things like corn and white bread are ingested into your body, their converted into sugars. Those sugars convert to insulin cuz it's fat cells go into storage overdrive, leading to weight gain. Since fewer calories are then left to fill the body, you begin to feel hungry it means our metabolism begins to slow down in effort to save energy, we eat more and we gain more weight, never quite feeling full. As this process repeats, our cells become more resistant to insulin, which causes us to gain more weight, which increases insulin resistance in a vicious circle. Cut calories, and people just get hungrier. Obesity, diabetes, high triglycerides and low HDL cholesterol can all follow. Study after study has found it's very difficult to lose weight on a very low- fat diet. Possibly because fat and meat can produce a sense of satiety, that's hard to achieve with carbs, making it easier to simply stop eating. But it isn't just the increase in carbs that affects us. These processed, low saturated fat alternatives, come loaded with sugars, salt, preservatives, and even some unhealthy fats. So what's the real alternative? As one extra puts it, the cold hard truth about diet is that the only way to eat well, is to eat well. You'll be happier and you'll be healthier, if you focus on real whole foods, whether they have fat or not. Got it. 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