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Intermittent fasting has generated much excitement over its potential  as a simple method to lose weight and improve health. It involves eating normally  during limited hours each day (e.g. 8 hours), and then abstaining from food the other hours (e.g. 16 hours). However, a recent study found that people following intermittent fasting for 12 weeks did not really lose weight or improve key metabolic markers. Bummer.

University of California researchers randomly assigned 116 adults, who were overweight or obese, to either an intermittent fasting group (16 hours fasting/8 hours allowed to eat ) or a group that ate 3 regular meals at set times each day (breakfast, lunch, dinner). The intermittent fasting group lost 2 pounds over the 12 weeks, which is not significantly different from the group that ate their meals at structured times - they lost 1 1/2 pounds. Same with metabolic markers (e.g.insulin levels, fasting glucose levels, cholesterol levels) - no real differences between the groups after 12 weeks.

Of course this was just 1 study, so we'll see what other human studies find. In contrast, other small human studies, as well as mice studies, have found health benefits from intermittent fasting, also called time restricted eating.

From Medical Xpress: Intermittent fasting is popular—but it doesn't work for weight loss

The currently popular diet of intermittent fasting that restricts eating to eight hours per day, separated by 16 hours of fasting, is not effective on its own as a means of either losing weight or for improving key metabolic health markers, according to a new study led by researchers at UC San Francisco.  ...continue reading "Intermittent Fasting Study Didn’t Find Expected Health Benefits"

Do you want to live longer and be healthy at the same time? Some possible ways may be to restrict the calories in the diet (every day) or to practice intermittent calorie restriction (a fasting mimicking diet a few days a month or even each week, such as the 5:2 diet). Previous studies in animals and humans have suggested that periodic fasting can reduce body fat, cut insulin levels, and provide other benefits. Studies in animals found that sharply restricting calories (calorie restriction or CR) daily resulted in longer, healthier lives, but it is unknown if the benefits of chronic calorie restriction also holds true for humans, and even if it might be dangerous. And really - how many people would actually want to reduce their calorie intake by 25% or more day in and day out for years? Intermittent calorie restriction seems much, much easier.

Two recently published studies suggest health benefits of calorie restriction diets - chronic calorie restriction in adult rhesus monkeys, and intermittent calorie restriction (a fasting mimicking diet a few days a month) in humans.

Researchers at the Univ. of Wisconsin–Madison and National Institute of Aging reanalyzed two studies they had originally done with conflicting results, and now they reported in Nature Communications that chronic calorie restriction produced health benefits (such as lower incidence of cancer, cardiovascular problems) and longer life in rhesus monkeys. Since these primates have human-like aging patterns, they thought that CR would also have similar benefits in humans - a longer, healthier life.  The researchers describe one monkey they started on a 30 percent calorie restriction diet when he was 16 years old (late middle age for rhesus monkeys), and that he is now 43 (a longevity record for the species). They found that in nonhuman primates calorie restriction is beneficial when started in adulthood (especially late middle age in males), but does not improve survival when started in juveniles (young animals) - and in fact they tended to die at an earlier age than the normal diet group of primates.

In the other study (in Science Translational Medicine), research suggests it is possible to gain anti-aging benefits with a “fasting-mimicking diet,” practiced just five days a month. 100 healthy adults (aged 20 to 70) were randomly assigned to either a group following a low-calorie "fasting-mimicking" diet (FMD) five days a month, for 3 months, or a normal diet control group. After 3 months, the control group also went on the fasting mimicking diet. Test subjects followed a 50 percent calorie restricted diet (totaling about 1,100 calories on the first day) and 70 percent diet (about 700 calories) on the next four days, then ate whatever they wanted for the rest of the month. The calorie-restricted diet was low in calories, sugars, and protein, was 100 percent plant-based, and featured vegetable soups, energy bars, energy drinks, and a chip snack, as well as mineral and vitamin supplements. (Note that Longo and Univ. of Southern California are both owners of L-Nutra, the company that manufactures the diet. But Longo says he takes no salary or consulting fees from the company.)

But it still wasn't easy for the test subjects to follow the 5 days of restricted calories per month because there was a 25% drop out rateHealth benefits (about a 6 pound weight loss, smaller waistlines, lower blood pressure, lower levels of inflammation, and better levels of glucose, triglycerides and cholesterol, etc.), showed up after the third month and persisted for at least three months—even after subjects had returned full-time to a normal diet. They lost body fat, but lean muscle mass remained unchanged. They found that the benefits were greater for people who were obese or otherwise unhealthy. In summary, the researchers said that 3 cycles of the 5 days per month of fasting-mimicking diet improved the levels of a variety of "markers/risk factors associated with poor health and aging and with multiple age-related diseases" (such as cancer, diabetes, heart disease, etc).

Other researchers say there is no need to suffer through such extreme diets, but to instead follow a healthy lifestyle, which includes a healthy diet (with lots of vegetables, fruits, legumes, seeds, whole grains, and nuts), and to exercise. And remember - nowhere does following restricted calorie diets mean you'll live longer - just that you should be healthier as you age (hopefully). There are no guarantees in life...

From Science Translational Medicine: Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease

Mice that fast periodically are healthier, metabolically speaking. To explore whether fasting can help people as well, Wei et al. studied 71 people who either consumed a fasting-mimicking diet for 5 days each month for 3 months or maintained their normal diet for 3 months and then switched to the fasting schedule. The fasting-like diet reduced body weight and body fat, lowered blood pressure, and decreased the hormone IGF-1, which has been implicated in aging and disease. A post hoc analysis replicated these results and also showed that fasting decreased BMI, glucose, triglycerides, cholesterol, and C-reactive protein (a marker for inflammation). These effects were generally larger in the subjects who were at greater risk of disease at the start of the study. A larger study is needed to replicate these results, but they raise the possibility that fasting may be a practical road to a healthy metabolic system.

From Nature Communications:  Caloric restriction improves health and survival of rhesus monkeys

The following article excerpts are from the talk "Food and Brain" about the best foods for the brain, at the annual 2015 meeting of the American Psychiatric Association (APA). This is in the new emerging field of food psychiatry, or how certain foods and diet influence the brain. The data is emerging that we can positively influence mental health through dietary interventions. For ex.: recent work reported that adults who followed the Mediterranean dietary pattern the closest over 4.4 years had a significantly reduced risk of developing depression (by 40% to 60%).

One key comment was: "Perhaps diet is the closest we've come to prevention in psychiatry." Some foods that are especially beneficial for the brain: seafood, greens, nuts, legumes (beans) and occasional dark chocolate. Use smaller amounts of meat (more as flavorings rather than just eating huge chunks of it) on top of a plant based diet. Also mentioned were the benefits of turmeric (because of the curcumin in it) and rosemary. And focus on improving the whole dietary pattern rather than just eating or not eating certain foods.

Note that BDNF is Brain-derived neurotrophic factor. This is a protein that acts on the brain, the nervous system, and it is very important for learning, memory, and higher thinking. So increasing BDNF levels is good. And remember, what's good for the brain is also good for the body and microbes - it's all intertwined. From Medscape:

Beans, Greens, and the Best Foods For the Brain

Dr Ramsey, in collaboration with the new International Society for Nutritional Psychiatry, is in the process of developing a standardized "brain food diet." "Food is a very effective and underutilized intervention in mental health," he started off. "We want to help our patients have more resilient brains by using whole foods...by helping get patients off of processed foods, off of white carbohydrates, and off of certain vegetable oils."

Though the field is in its infancy, food psychiatry is increasingly being embraced by clinicians and researchers, as a paper published earlier this year in the Lancet Psychiatry attests. "Although the determinants of mental health are complex," the authors wrote, "the emerging and compelling evidence for nutrition as a crucial factor in the high prevalence and incidence of mental disorders suggests that diet is as important to psychiatry as it is to cardiology, endocrinology, and gastroenterology." ..."The data are very promising that we can positively influence mental health through dietary interventions," commented Dr Ramsey.

"Hominid diets have changed drastically through millions of years of evolution.,,,But only in the past 100 years has our diet drastically switched from a whole foods diet to one that is more processed and high in refined carbohydrates; that includes more vegetable fats rather than meat fats; and preservatives, emulsifiers, and other additives, which appear to have contributed to a decline in our collective health.

Early humans evolved in the African Rift Valley, which is near a seacoast. It's possible that whatever evolutionary spark occurred that made us human occurred here, in part due to reliable access to seafoodoysters in particular—which glutted our brains with omega-3 fatty acids and cholesterol (our brains are composed of 60% fat). Oysters and other mollusks are also very high in nutrients, including B12, which is commonly deficient in people consuming vegan or vegetarian diets and is necessary for myelin and neurotransmitter function. 

A number of studies have linked the Mediterranean diet (high in fish oils, nuts, and grains and including maybe a little red wine) with advantageous effects on neurologic and mental health. Dr Deans cited recent work reporting that adults who followed the Mediterranean dietary pattern the closest over 4.4 years had a significantly reduced risk of developing depression (40%-60%)....When taken together, most of these dietary pattern studies, which have been conducted all over the world, consistently show that traditional, pre-processed diets are the healthiest, including for the brain. ..."Eat the rainbow," he says, given that bold, bright colors in nature tend to signify valuable vitamins and phytonutrients (the reds, purples, and greens in particular).

Seafood: Seafood is packed with brain-healthy omega-3 fatty acids. These healthy fats are also abundant in plants like chia and flax, but plant-based sources aren't as efficiently converted to docosahexaenoic acid (DHA), an important structural component of neuronal membranes. DHA also influences the expression of brain-derived neurotrophic factor (BDNF), which can benefit people who have mood and anxiety disorders. Bivalves like mussels, oysters, and clams are the top source of vitamin B12 as well as zinc: Six oysters (only about 10 calories each) provide 240% of our recommended daily B12 intake and 500% of our recommended zinc intake! Seafood is also a leading dietary source of vitamin D (we don't get it all from the sun) as well as iodine and chromium. Although many people worry about mercury in fish, Dr Ramsey provided an easy way around the concern: Eat small fish like sardines, anchovies, and herring, which typically don't accumulate toxic levels.

Leafy greens: A great base for a brain-food diet, leafy greens are a good source of fiber, folate (derived from the wordfoliage), magnesium, and vitamin K. Perhaps surprising, kale, mustard greens, and bok choy provide the most absorbable form of calcium on the planet, more so than milk. Greens also provide flavanols and carotenoids that have beneficial epigenetic influences (eg, including upping hepatic toxin processing). 

Nuts:... Nuts are packed with healthy monounsaturated fats. They help keep us full and also aid in absorbing fat-soluble nutrients. Nuts also provide fiber as well as minerals like manganese and selenium. A serving of 22 almonds (just 162 calories) contains 33% of our recommended vitamin E, plenty of protein, and minerals, including iron. One study from 2013 found that the Mediterranean diet augmented with nuts is associated with significantly higher BDNF levels in patients with depression.

Legumes: Dr Ramsey is pro-meat, but he acknowledges that many people are eating far too much and the wrong types of meat, and that nuts and legumes are a great alternative source of protein and nutrients...Some data suggest that vegan and vegetarian diets are associated with improved mood. But as previously mentioned, these dietary patterns can result in B12 deficiency, which has been associated with brain atrophy and developmental delay. Hence, supplementation is important in this population. Vegetarianism has also been linked with depression, anxiety, and eating disorders, as well as increased healthcare utilization and worse quality of life. These negative associations also could be due to the fact that it's harder to absorb nutrients like zinc, iron, and certain omega-3s from plants.

"The notion that the vegan diet is the healthiest diet on the planet is probably incorrect," said Dr Ramsey, before explaining that he just feels that we should approach meat in our diets differently....We want to help patients use beef and seafood more as flavorings on top of a plant-based diet." A modest amount of meat in the diet has its benefits, including nutrient availability: Hemoglobin-derived iron is up to 40% more absorbable than plant-based iron. Unlike most plants, meat provides all of the amino acids necessary for protein synthesis. Dr Ramsey emphasized the importance of seeking out leaner, grass-fed meats if one has the means.

The understanding of how microbiota contribute to our mental and medical well-being is rapidly advancing....One of the most powerful interventions to alter our microbiome is diet. Research shows that stressed mice experienced changes in the gastrointestinal microbiota, reflecting the gut-brain relationship. There are 260 million neurons connecting the gut and the brain; furthermore, many commensal gut bacteria make neurotransmitters and communicate with the brain via the vagus nerve....Although the science of probiotic therapies is relatively young, it's clear that these commensal organisms co-evolved with us and are adapted to our diet.

Finally, to close out the session, Dr Ramsey returned to the stage and asked, "So, can you eat to build a better brain? We think that you can if you focus on dietary patterns and not a single food here or there." He also reminded the audience to help their patients identify and increase their consumption of nutrient-dense foods and to "eat the rainbow,"..."I don't know of anything else that can potentially decrease the risk of depression in a population by 40%," he concluded. "Perhaps diet is the closest we've come to prevention in psychiatry."

...Evidence suggests that curcumin, an ingredient in turmeric, increases BDNF. Other research has found that populations that eat more curry have a decreased risk for dementia, while rosemary extract may help prevent cognitive impairment. "Many spices seem to have healing properties," Dr Ramsey commented.

Although the "Food and the Brain" session at the American Psychiatric Association annual meeting focused on what to eat in the interest of brain health, intermittent fasting might also be beneficial for the brain. In addition to helping maintain a healthy weight, fasting induces ketosis. Ketone metabolism has been shown to be beneficial for the brain and improve cognition in patients with mild cognitive impairment or Alzheimer disease. Keep in mind that fasting can come with risks for some people, particularly diabetics, and should be discussed with a healthcare provider.

Here is an article to what I referred to in my recent Feb. 27 Feast and Famine Diet post about intermittent fasting being beneficial to health and resulting in weight loss. This definitely seems easier than sticking to very low calorie diets weeks on end. From NPR:

Minifasting: How Occasionally Skipping Meals May Boost Health

If you've ever gone to sleep hungry and then dreamed of chocolate croissants, the idea of fasting may seem completely unappealing. But what if the payoff for a 16-hour fast — which might involve skipping dinner, save a bowl of broth — is a boost in energy and a decreased appetite?

This is what we've experienced as we've tried out the so-called 5:2 diet. It's an intermittent fasting approach that, as we've reported, has been popularized by books by British physician and television broadcaster Michael Mosley. The diet calls for two days per week of minifasting where the aim is to go a long stretch, say 14 to 18 hours, without eating. During these two fasting days, you also eat only about 600 calories, give or take. But here's the easy part: The other five days of the week you forget about dieting and return to your normal pattern of eating.

The fascination is what researchers say may be the broader benefits. Scientists are looking into how fasting may help control blood sugar, improve memory and energy and perhaps boost immunity. A study by researchers at the University of Manchester found that when overweight women followed a 5:2 approach, they lost more weight and body fat and improved their insulin resistance compared with women who followed a more traditional diet of limiting calories seven days per week.

One explanation for the success of the 5-2 dieters could be that a day of minifasting can lead to a diminished appetite. As Allison reports on All Things Considered, she found that she's just less hungry the day after a fast.

Mark Mattson, a researcher at the National Institute of Aging, says when we go without food, the body uses up its stored glucose, the basic fuel for the body, and starts burning fat....During fasting, he says, fat can convert to compounds called ketones, "which have beneficial effects in making neurons more resistant to injury and disease.

There may be an evolutionary explanation for this because humans (and other animals) have fasted intermittently for much of our time on Earth, after all. As a recent paper in the Proceedings of the National Academy of Sciences notes, "The most common eating pattern in modern societies, three meals plus snacks every day, is abnormal from an evolutionary perspective."

Longo and other experts gave Eliza some of their other tips on how to do it right: - Fasting is easier with a buddy. - On a minifast, choose the food you do eat carefully. Researchers recommend high-protein, high-fiber foods. Avoid refined carbs and sugar, which will spike blood sugar and may leave you hungry late in the day. - To minimize temptation, stay out of the kitchen and away from food establishments. - Try a pattern of weekly intermittent fasting for at least a month. Studies have shown that a long-term lifestyle change (and the benefits associated with it) is more likely for people who can stick with the diet for at least a month. And tolerating some hunger gets easier the longer you do it. - Don't be surprised if there are some side effects, like trouble sleeping or gastrointestinal issues.