The Truth About Intermittent Fasting: Is It Good for Weight Loss and Overall Health?
Ask Keri: It seems like everyone is talking about intermittent fasting. As an RD, do you recommend the practice? Keri says: It really does feel like absolutely everyone is preaching the benefits of intermittent fasting. Weight loss! Brain health! A longer life! My perspective, in a nutshell, is that the evidence on its health and weight-loss benefits are definitely compelling. However, it’s a practice that requires regimented commitment that many people will find is too difficult to fit into their lifestyle, depending on their work hours, social life, and other factors. If you’re not super diligent, you won’t be able to reap the rewards. Here are the details you need to figure out if it’s right for you. What is intermittent fasting? Intermittent fasting is a broad term that covers a pattern of eating that involves a set amount of time where you don’t eat (or eat an incredibly restricted number of calories), followed by one in which you do. The most popular version involves fitting all of your daily food consumption into an eight-hour window, followed by 16 hours of fasting. For example, you could eat between 10 a.m. and 6 p.m. every day and fast between 6 p.m. and 10 a.m. (including the hours you’re asleep). There’s also the 5:2 diet in which you split your week into five days of eating whenever you want and two days where you seriously restrict your calories—500 for women, 600 for men. (Personally, I find this one to be the easiest of the options.) While fasting may seem extreme and irregular, proponents argue that humans actually ate this way for most of history, since hunters-gatherers ate when food was available, not at set mealtimes. Plus, fasting is an age-old part of nearly every religious tradition. The potential benefits of intermittent fasting The research on the health benefits of intermittent fasting is pretty interesting. Most people try it for weight loss. Research backs up its effectiveness in patients with Type 2 diabetes. The most basic reason it can work for weight loss is that you’re simply going to eat less when restricting calories to set time periods. Fasting also reprograms your metabolism. When your body isn’t getting energy from food, it turns to its other fuel source: stored fat. By breaking down more fat and shrinking the size of fat cells, you end up with fat loss, and as a result, weight loss. RELATED: Why Healthy Fats Don’t Make You Fat In terms of the bigger health picture, studies link intermittent fasting to reducing markers of inflammation. They also show fasting can affect hormones, increasing production of beneficial ones like HGH (for muscle gain and fat loss) and BDNF (for cognition) while decreasing insulin levels. Fasting may lead to improvements in pancreatic B-cell function and the regulation of the circadian rhythm, which promotes better glucose tolerance. In a randomized controlled study of more than 100 overweight or obese women, six months of intermittent fasting reduced insulin levels by 29% and insulin resistance by 19%. Reductions in fasting insulin and insulin resistance were modest in both the intermittent fasting and continuous energy restriction groups, but greater in the intermittent fasting subjects. Another study on non-obese subjects also found that fasting decreased insulin levels and increased fat oxidation—the process that breaks down fat during energy restriction or exercise. Studies have found that fasting may improve depression and stress levels, and encourage overall positive psychological shifts. Research (some in animals, some in humans) even suggests intermittent fasting’s cardiovascular and brain health benefits could extend lifespan. There are certain groups of women who it may work well for. It’s important to monitor how you feel, how you are sleeping, what your mood is like and what your menstrual cycle is like as well. Also, it may be helpful for women with PCOS. Like most things with diet, it is very individual and if you choose to give it a go, you should probably work with an RD or nutrition coach. RELATED: 5 Foods for Brain Health Are there risks to intermittent fasting? So far, this all sounds really good, right? But there are, of course, caveats. Low calorie intake always comes with risks, which is why it is important to ensure that you are getting adequate calories and proper nutrients while following this style of eating. Hunger can be a real issue, which, in turn, can lead to stress. Prolonged stress of any sort can increase inflammation in the body. RELATED: 7 Delicious Anti-Inflammatory Foods to Eat Daily Confining yourself to a specific way of eating for a short time can also lead you down a long road of yo-yo dieting, and some argue that fasting can lead to disordered eating. Finally, the results of some animal studies suggest intermittent fasting could affect fertility in women, so you should skip it if you’re trying to get pregnant. The bottom line At the end of the day, my feelings on intermittent fasting boil down to a few questions: Is it going to be doable for you? Will it make healthy eating easier or harder for you? Some people say it simplifies their eating, but if you work long, unpredictable hours and have trouble planning meals ahead, trying to stick to a plan like this may drive you crazy. It also won’t work if you’re someone whose social life often revolves around food. Spontaneous dinner dates with friends or late-night tapas after a concert? Buh-bye. If you do think it might work for you, make sure you’re still eating in a healthy way, which means getting all of the proper nutrients from the calories you are consuming. Focusing on real, whole foods and skipping the junk will prevent nutrient deficiencies. If it sounds like the wrong approach, don’t beat yourself up about missing out on potential benefits. Just continue with a balanced, healthy diet and be mindful of your hunger quotient to keep overeating at bay and maintain a healthy lifestyle.
What Women Over 50 Should Know About Intermittent Fasting
For women over 50, weight loss can seem like a struggle for a variety of reasons—most of them related to a shift in hormonal balance. It’s no wonder that intermittent fasting has become so popular for women over 50 with its promise of amping up metabolism, reversing cellular damage (and its signs of aging), and improving mental clarity. Let’s take a look at what happens to women’s hormones as we approach and enter menopause, and what the science says about whether intermittent fasting can help counter some of these imbalances. Hormones and Women Over 50 During perimenopause and menopause, estrogen fluctuates and becomes unpredictable before falling to very low levels. This decline in estrogen comes with shifts in other hormones like cortisol, thyroid hormones, serotonin, and sex hormones. These hormonal shifts are what lead to some of the symptoms of menopause. You may become less sensitive to insulin during menopause, leading to difficulties processing sugar and refined carbohydrates. This is known as insulin resistance, which might make you more susceptible to gaining weight around your midsection. Muscle mass may also diminish as fat increases, leading to less metabolically active tissue and difficulty maintaining a healthy weight. RELATED: Thyroid Disease and Diet: Managing Thyroid Health With the Right Nutrients Cue intermittent fasting. With this unorthodox way of eating touting benefits for healthy aging, there’s no wonder that IF has been popular with perimenopausal and menopausal women. But does the research hold up? What is intermittent fasting? In short, intermittent fasting involves eating within a specific time window. The most popular version involves fitting all of your daily food consumption into an eight-hour window, followed by 16 hours of fasting. For example, you could eat between 10 a.m. and 6 p.m. every day and fast between 6 p.m. and 10 a.m. (including the hours you’re asleep). There’s also the 5:2 diet in which you split your week into five days of eating whenever you want and two days where you seriously restrict your calories—500 for women, 600 for men. While fasting may seem extreme for some, proponents of this dietary pattern claim that fasting causes your body to use stored fat as fuel. RELATED: The Truth About Intermittent Fasting: Is It Good for Weight Loss and Overall Health? How does intermittent fasting work? What’s the evidence? The research on the health benefits of intermittent fasting is pretty interesting, with the latest findings adding a bit of inconsistency compared to previous results. A study comparing two groups—a calorie-restriction-only group and a calorie-restricted and time-restricted eating group—followed subjects over the course of one year and found no effect on body weight, body fat, or metabolic risk factors. People who only ate from 8 a.m. to 4 p.m. didn’t lose significantly more weight than those who ate any time throughout the day. Any weight loss was attributed to overall caloric restriction rather than time-restricted eating regimens. Other findings, however, have shown benefits for weight loss, insulin resistance, mental health outcomes, and brain cell activity. Let’s take a look at a few of those. Weight loss Studies have found that intermittent fasting can help with fat loss by reducing body mass and improving metabolic health. They also show fasting can affect hormones, increasing production of beneficial ones like HGH (for muscle gain and fat loss). Still, these effects appear broadly comparable to standard daily calorie restriction. In a study that compared the weight loss efficacy of alternate-day fasting (ADF) among pre- and post-menopausal women, body weight significantly decreased from baseline in both groups. This suggests that intermittent fasting may be effective in weight loss regardless of menopausal status. Another study looked at time-restricted feeding and found similar results. Both pre- and post-menopausal women lost weight and showed metabolic improvements. Insulin resistance Intermittent fasting’s effect on insulin sensitivity has been a hot topic in recent years. Researchers hypothesize that this is achieved by flipping a metabolic switch. Fasting leads to lower levels of glucose (i.e. blood sugar) and in response, the body uses fat instead of glucose as a source of energy. Fasting can also lead to improvements in pancreatic B-cell function and the regulation of the circadian rhythm, which promotes better glucose tolerance. In a randomized controlled study of more than 100 overweight or obese women, six months of intermittent fasting reduced insulin levels by 29% and insulin resistance by 19%. Reductions in fasting insulin and insulin resistance were modest in both the intermittent fasting and continuous energy restriction groups, but greater in the intermittent fasting subjects. Another study on non-obese subjects also found that fasting decreased insulin levels and increased fat oxidation—the process that breaks down fat during energy restriction or exercise. In one study, researchers looked at the effects of intermittent fasting versus continuous calorie restriction on HbA1c (a measure of average blood sugar levels over the past 3 months) in diabetics over the age of 50. They found that a two-day intermittent calorie restriction diet was comparable to a continuous calorie restriction diet for improvements in blood sugar control. Mental health changes Menopause can cause anxiety, depression, fatigue, brain fog, mood swings, and psychological stress. Studies have found that fasting can improve depression and stress levels, and encourage overall positive psychological shifts. It is important to note that both of these studies were conducted in age ranges below 50 years old. Brain fog Studies in animals have found that fasting can have positive effects on brain cells, by encouraging better stress responses and clearing out damaged cells in order to regenerate newer, healthier cells. Fasting has also been shown to increase BDNF expression in rats, a protein that serves as a sort of fertilizer or “miracle-grow” for the brain. There are no studies on how fasting affects the human brain yet, but one of the most common things people report while fasting is increased mental clarity. Bottom Line: Intermittent Fasting for Women Over 50 While intermittent fasting shows promise, we don’t have solid evidence about the benefits or how fasting might affect
Is Intermittent Fasting Bad for You? Skip If Any of This Applies to You
Intermittent fasting (IF) has everyone buzzing. In fact, it ranked as the #1 diet trend in Google’s 2019 Year in Search, and the latest research published in the New England Journal of Medicine reports that a six-hour eating window followed by an 18-hour fast might lower risk for cancer and obesity and increase longevity. But what is IF, really? “Intermittent fasting is incorporating extended periods of limited or no food intake into your eating schedule,” says Ashley Reaver, a registered dietitian at Ashley Reaver Nutrition LLC. “There’s no intentional change or focus on the types or amounts of food you eat within the ‘feeding window.’” Proponents claim that the fast-then-feast strategy works magic on your metabolism and promotes weight loss. IF comes in many forms, including the trendy reality TV star-created Dubrow Diet (involving 12 to 16 hours of fasting per day), alternate-day fasting, 16:8 (fasting for 16 hours, then eating during the following 8-hour window), 5:2 (eat normally for five days, then limit yourself to around 500 calories per day for the next two), and the Warrior Diet (fast during the day, then eat one large feast during a four-hour span at night). RELATED: Why Harley Pasternak Says Most Popular Diets are Fads, and How He Eats Instead “The most popular kind at the moment is time-restricted eating, where you limit your intake to a specified period of time each day. This usually ranges from six to 12 hours,” Reaver says. While the most recent science stands behind the disease-prevention benefits of IF—that is, if you can stick with it for the long-term. Like with all diets, there are certain people who should steer clear of intermittent fasting. Who Should Steer Clear of Intermittent Fasting? Anyone with a history of eating disorders Whether it’s anorexia, bulimia, binge eating, or otherwise, “people with a history of eating disorders or disordered eating should absolutely not begin intermittent fasting,” Reaver says. “Likewise, those recovering from eating disorders should not focus on an arbitrary timeline for eating.” Strict food rules like these can be triggering or lead to a binge. People who love breakfast If you can’t start your day without a bowl of oats or a plate of eggs, you’ll likely want to pass on the fasts. Since the eating window can be as small as six hours, if you want to dine with your family at dinner, your first bite of the day will likely come after noon. “Breakfast can help set up your healthy routine for the day,” says Keri Glassman, RD, the founder of Nutritious Life, so if you are hungry enough to eat in the a.m.—and enjoy doing so—avoid IF. RELATED: 10 Healthy Breakfasts You Can Make In 10 Minutes or Less Anyone with diabetes or blood sugar-related conditions “Those with diabetes also should not begin intermittent fasting, particularly if eating in the morning will be pushed back,” Reaver says, as blood sugar control is vital. Eating at regular intervals throughout the day helps the body avoid the sharp blood sugar highs and lows that can come with the feast-then-fast cycle. Athletes To crush that next personal best, you need enough gas in the tank. Think of your body like a car. If you don’t refuel often enough, it’ll stall out. “If performance is your main goal, limiting caloric intake and impeding nutrient timing around workouts will negatively impact muscle growth and recovery,” Reaver says. The Bottom Line Like nearly everything in the wellness world, there is no one-size-fits-all solution. Including IF. “Some people should certainly avoid it,” Reaver says. “But I do believe that eating on a consistent schedule when possible is beneficial for health. Our bodies like routine, and eating around the same times each day is a good pattern.” If fasting helps you stay on that schedule, and you don’t fall into any of the categories above, then IF might work for you. But again, if you like breakfast, feel free to skip this one. (Photo: Shutterstock)
