Can't quite fasten those jeans? Avoiding the mirror? Feel bloated and tired? Welcome to the post-holiday blues.
Studies indicate that most people don't gain as much weight as they think over the holidays—the average Western man or woman gains only one or two pounds during the month of December. But it sure feels like more. It's cold and wintery (unless you live in a more tropical zone), the shopping bills are coming in, and because you (like most people) didn't get around to losing the extra pounds gained over last year's holidays, you're feeling far less than optimal.
It's definitely time for something to help kick-start your metabolism (and your mood) as you settle into the new year. But fasting? Isn't that a little extreme?
Eating nothing for days, only drinking water to keep the body hydrated, is something most people used to do only for religious purposes or as a last resort because of severe illness. Water fasts, by their very nature, are extreme. Yet, they are sometimes still recommended for people with certain conditions.
Studies show that water fasting triggers a process called autophagy, where old cells are broken down and eaten by the body, which can benefit people suffering from cancer, neurodegeneration and microbial infections.1 Water fasting has been shown to increase autophagy and improve signs of aging in the brain and might help reduce the risk of Alzheimer's disease.2
Medically supervised water-only fasting has also been shown to lower blood pressure in patients suffering from hypertension,3 and it significantly reduces the blood levels of cholesterol and triglycerides thought to contribute to cardiopulmonary disease.4
Short-term fasts of no more than 48 hours were able to protect normal cells in mice, but not cancer cells, against high-dose chemotherapy. And human patients undergoing chemotherapy reported a reduction in gastrointestinal side-effects, fatigue and weakness while fasting.5
Because the average person can lose around six pounds in 72 hours on a water fast, many think that it's the best way to achieve rapid weight loss. On the surface, this might sound like an excellent post-holiday quick fix to the weight issue. Unfortunately, it's not as effective as it seems.
For starters, it's tough. For those of us accustomed to three square meals plus snacks and a morning latte every day (never mind all the Christmas party fare everyone's just eaten), that's going to take a lot of willpower. Plus, only about 5 percent of people who lose weight on a crash diet (which a water fast definitely is) keep the weight off.
Water fasts, which should not be done unsupervised for over 72 hours and not at all by anyone with any sort of health problem, trigger a dump in water weight—that is why the results are so impressive. But they don't necessarily trigger fat burning. Indeed, you can actually lose lean muscle weight on a water fast.
There can also be serious side-effects. For people with diabetes, not eating when taking insulin or certain other diabetes medications can wreak havoc on blood sugar levels, raise the risk of hypoglycemia (low blood sugar) and much worse. Because fasting also leads to rapid loss of sodium and potassium, the risk of postural hypotension (low blood pressure when standing up) and fainting increase. And severe potassium depletion can cause heart arrhythmias.6
The good news is, water fasting isn't the only way to fast anymore.
The intermittent fast
By far the most popular approach to fasting now is intermittent fasting (IF), which operates just like it sounds. You alternate periods of eating with periods of not eating.
Unlike a diet, which involves regulating, restricting and/or eliminating certain foods, and closely monitoring caloric intake, this approach is a way of controlling weight and improving one's health by changing your pattern of eating. It doesn't involve what you eat so much as it entails regulating when you eat.
Intermittent fasting is also known as time-restricted feeding. The best-known intermittent fast is called the 16:8 protocol, popularized as the 'Leangains Method,' where the eating window is eight hours and the fasting window is 16 hours in length every day.
Other variants tweak this time ratio, but no matter what it is, if you are fundamentally healthy, you can practice IF over any length of time, from a week to a lifetime.
Sonia Wisinger, a certified health coach and fasting coach in London, UK, recommends IF as a lifestyle. "Every Sunday I chart out which days I'm going to skip dinner and use as a fasting day and which days I will eat normally," she says.
One of the first studies done on athletes using this method found that, although weight loss was not significant, fat levels decreased in individuals on the 16:8 fasting protocol but not in the control group, who stuck with their normal eating patterns (breakfast, lunch and dinner at approximately 8am, noon and 7pm).
In addition, the IF group had reduced levels of testosterone, IGF-1 (insulin-like growth factor 1, a hormone similar in molecular structure to insulin), insulin, blood glucose, triglycerides and pro-inflammatory cytokines, a marker of inflammation in the body.7
The 16:8 method has been called a glorified way of saying "skip breakfast." But, according to some fasting experts, skipping breakfast is about the worst way to implement this fast. Skipping dinner is by far the better choice.
"Because of our lifestyle, nowadays the biggest meal of the day comes in the evening," says Wisinger. "Eating in the evening doesn't do anything for you in terms of skin health, in terms of your waistline, in terms of feeling well, sleeping well, feeling relaxed, or having time and attention for your family."
Wisinger, who trained at a fasting clinic in Austria, says intermittent fasting has been popular with the anti-aging crowd in Europe back in the 1990s. "We called it dinner canceling," she laughs. "And all my clients love it.
"If you do dinner canceling, usually you will wake up with the sun, and you will also have the wish to go to bed earlier. You sleep more deeply, and you will have all this time in the evening to take care of your family, to be alert, to play with your children and to prepare your meals for the next day."
The mechanism behind IF (which is also known as periodic fasting) is simple. The carbohydrates we eat are broken down by enzymes in our gut and enter the bloodstream as sugars that feed the body's cells with energy. If our body doesn't need all that sugar to feed cells, it stores the excess sugar as fat, with the help of insulin secreted by the pancreas.
As long as we don't snack in between meals, our blood insulin levels go down, and our fat cells can then release their stored sugar to be used for needed energy. The whole idea of IF is to allow the insulin levels in the body to go down far enough and for long enough that we burn off our fat.
Variations on the 16:8 protocol change the eating and fasting windows to ratios of 14:10 or 12:12. Some people with slow metabolisms find that it's necessary to restrict eating to as little as a six-hour window or even a five- or four-hour window (18:6, 19:5 or 20:4, respectively). Anything below a 12-hour fasting window is considered insufficient to ignite the fat-burning process.
Another intermittent approach is the 5:2 diet, which first started gaining popularity in 2012. The 5:2 diet means limiting your caloric intake to 500 calories per day for two (nonconsecutive) days during the week, while eating a regular healthy diet the rest of the week, with a diet of approximately 2,000 calories per day for women and 2,500 calories for men.
A more extreme approach to the 5:2 diet (and one that results in faster weight loss) is to pick two nonconsecutive days per week where you don't eat for the entire day (24 hours), while maintaining a healthy diet the other five days.
Studies on intermittent and periodic fasting have been conducted for years on rats and mice, and only more recently with humans. IF has been proven to reduce oxidative damage and inflammation, boost energy and increase the protection of cells. In humans, it appears to improve obesity, hypertension, asthma and rheumatoid arthritis.8
In animals, intermittent or periodic fasting has shown benefit against cancers, diabetes, heart disease and neurodegeneration, and it was as effective as pharmaceutical drugs for reducing brain seizures and seizure-induced brain damage.9
It also promotes stem cell-based regeneration10 and mitigates age-related cognitive decline.11
The Buchinger/Luetzner method and the alkaline fast
In recent years, particularly in the English-speaking world, fasting has been reduced in most people's minds to a weight-loss program.
But there are many reasons why you might want to fast, says Wisinger, and her most important role is to determine the type and length of fast an individual should follow, based on their current condition and whether they have an illness or just a desire to lose weight.
For people who are grieving or who have experienced a loss, whether of a job, a pet or a romantic partner; people who suffer from burnout, like nurses who work in intensive care units; and people who are stuck with a major problem at home or in the workplace, she recommends the Buchinger/Luetzner fast.
Developed by Dr Otto Buchinger in the early to mid-20th century and popularized by another German physician, Dr Hellmut Luetzner, this deep fast lasts five to 10 days on average, enabling you to "really detach from the world." For certain health conditions, the fast can last as long as 21 days.
On the Buchinger/Luetzner fast, no solid food is taken, and the daily caloric intake from vegetable broths, fruit juice and certain herbal teas is between 200 to 300 calories per day, with one piece of fruit each morning included.
For clients presenting with chronic pain or ill people who have received no help from conventional medicine, she recommends something called an alkaline fast, where only alkaline-producing foods such as vegetables and fruits, nuts and seeds are eaten.
The alkaline fast limits daily calorie consumption to around 900 calories and lasts, on average, for five to 10 days—although, depending upon a person's health circumstances, it can be done longer. All animal protein, dairy, and other acid-forming foods (such as coffee, black teas and alcohol) are eliminated.
Wisinger recommends this fast for people with skin problems, gastrointestinal diseases, allergies, autoimmune diseases or chronic inflammation because it reduces C-reactive protein, which is produced in the liver during episodes of acute inflammation or infection.
"One of the keys to effective fasting is for people to actually stop counting calories, learn to stop snacking and give more importance to set mealtimes," says Wisinger.
The fasting-mimicking diet
One of the most novel approaches to fasting is something called the fasting-mimicking diet, or FMD. It follows the same principles as regular fasting, with the main difference being that instead of eliminating all food for a set period of time, you heavily restrict calories for only five days out of the month.
In essence, the diet is designed to trick your body into thinking it's not getting any food at all for that five-day period, even though you are eating—hence the reference to mimicking. The FMD can be done every month indefinitely. But ideally, it should be conducted under the supervision of a dietician or fasting expert trained in the protocol.
During day one of the diet, dieters are restricted to 1,100 calories. For the remaining four days, they're restricted to 800 calories a day. But it's not only the amount of food you eat that matters on this diet. It is very much about what you eat. The ratios of protein to healthy fats to carbohydrates are very exact.
"The body is always fed," says Dr Valter Longo, biogerontologist, cell biologist and creator of the FMD. "Sometimes it is fed from the outside (external food sources), and sometimes it's fed from the inside (autophagy, where the body feeds upon itself during fasting).
"We can only go without feeding the brain for a few seconds, as if the body needs continuous feeding, otherwise we die very rapidly. The trick is to confuse the brain about where the source of food is coming from. The body has to recognize it as an internal source and not an external one."
Longo points out the beauty of fasting and FMD is that it replicates the way we ate for millions of years before modern agricultural practices in the last 100 years made food readily available to most people.
"Imagine 5,000 years ago," he says. "People go for a month with no food. You've gone through the summer where there was plenty of fruit and nuts and maybe some fish and some other animal protein. And then all of a sudden it starts snowing, and for a month and a half you have no food at all.
"Now your body must go to many of the organs for sustenance. The lungs, the muscles, the liver will all shrink.
"The body eats itself until you start feeding again, and everything starts to rebuild. And that rebuilding is very much the same process that was used when you were first born. That is the power of fasting and doing this. We have the ability to rebuild organs in a super-coordinated manner that is embryo-like."
Studies in mice show that the FMD decreases risk factors for signs of aging, diabetes, cardiovascular disease and cancer. It reduces blood glucose levels and serum insulin levels, and it also affects adipose tissue and visceral fat deposits, leading to a reduction in body weight.
The FMD has even been shown to delay the onset of tumors while curtailing age-related bone loss and triggering bone regeneration.12
Benefits of fasting
According to Sonia Wisinger, certified health coach and fasting coach, there are many overall benefits to fasting, including:
• Mobilizes the body's defense mechanisms
• Cleanses the body
• Gives the digestive organs a rest
• Helps prevent chronic and acute disease
• Reduces body weight
• Supports maintenance of a healthy body mass index (BMI)
• Increases energy and vitality
• Increases serotonin levels resulting in improved sleeping patterns
• Quiets both the body and mind
• Helps to prevent signs of premature aging
• Clears away redness for sparkling eyes
• Healthier hair and nails
• Increases inner strength and focus
• Promotes better eating habits
• Fosters better impulse control
• Restores the ability to eat moderately and sensibly
The FMD & Daily Longevity Diet
For best results, Dr Valter Longo recommends combining a five-day fasting-mimicking diet (FMD) with what he calls the Daily Longevity Diet. For five days per month, follow the FMD plan. Then follow the longevity diet.
Day 1: Restrict calories to 1,100 on the first day. Eat plant-rich whole foods (preferably organic) that consist of 34 percent carbohydrates, 10 percent protein and 56 percent fat. (Nuts and olives can provide healthy fat.) Eliminate caffeine, coffee, and green and black teas. Substitute with herbal teas. Eliminate alcohol.
Days 2-5: For the remaining four days, calories are restricted to 800 per day. Continue to eat a diet rich in plants and whole foods, with an emphasis on nuts and olives. You may also enjoy vegetable soups and broths, as well as herbal teas. Eliminate caffeine, coffee, and green and black teas. Substitute with herbal teas. Eliminate alcohol. The general macronutrient recommendation for days two through five consists of 47 percent carbohydrates, 9 percent protein and 44 percent fat.
A five-day pre-made FMD series of meals designed by Dr Longo called The ProLon Fasting Mimicking Diet is available at: www.prolonfmd.com.
Maintain the Daily Longevity Diet
Days 6-31: Eat mostly vegan, plus a little fish, limiting fish to a maximum of two or three portions per week. Choose fish, crustaceans and mollusks with high levels of omega-3, omega-6 and B vitamins (like salmon, anchovy, sardines, cod, sea bream, trout, clams and shrimp).
For people up to 65 years old, keep protein intake low: 0.01 to 0.013 oz (0.31 to 0.36 g) per pound of body weight daily, which translates to between 1.4 and 1.7 oz of protein per day (40 to 47 g) for a person weighing 130 pounds, or 2.1 to 2.5 oz (60 to 70 g) for someone weighing 200 pounds.
Over age 65, slightly increase protein intake but also increase consumption of fish, eggs, white meat and products derived from goats and sheep to preserve muscle mass. Consume beans, chickpeas, green peas and other legumes as your main source of protein.
Minimize saturated fats from animal and vegetable sources (meat, cheese) and sugar, and maximize good fats and complex carbs. Eat whole grains and large quantities of vegetables with generous amounts of olive oil (3 tablespoons per day) and nuts (roughly 1 oz or 30 g per day).
If you are overweight or tend to gain weight easily, eat two meals a day (breakfast and either lunch or dinner) plus two low-sugar (less than 5 g) snacks of no more than 100 calories each.
If you are either at a normal weight or tend to lose weight easily or are over 65 and of normal weight, eat three meals a day and one low-sugar snack with fewer than 100 calories.
Confine all eating to within a 12-hour period, ideally starting at 7am and ending before 7pm. Do not eat within three to four hours of bedtime.
At the end of the month-long period, you can either come off the Daily Longevity Diet or maintain it. It is, after all, a longevity diet, designed to produce optimum health, wellbeing and longevity—and who wouldn't want that? You can also choose to include FMD occasionally or even every month.
Things to limit or avoid: Alcohol, caffeine, sugar, processed foods
WARNING: Even though initial studies indicate that FMD may be of assistance for people with diabetes, Longo warns that more tests need to be done. If you have diabetes, do NOT follow any kind of fasting-mimicking diet even under a doctor's supervision.
A good time to fast
Whether you're doing it for health reasons, to lose weight or to get better control of your eating habits and diet, January is a good time to ride the power of those New Year's resolutions and do a fast. "It's a very good idea to fast in January," says Wisinger. "You don't want to let those additional pounds sit and settle. Otherwise, it will be difficult to get rid of the excess weight."
If you plan on fasting, be aware that it takes longer than you might think. Wisinger says most people come to her thinking a five- or 10-day fast takes just that—five or 10 days. They are very surprised to discover it takes 15 to 30 days, or even longer depending on their health.
Both Longo and Wisinger are adamant that, for safety and health reasons, you should only fast under the supervision of a clinically trained fasting expert—most doctors are not trained to understand fasting and the proper protocols.
Both also stress the critical importance of preparing the body properly before going into a fast, gradually eliminating unhealthy foods such as sugar, gluten, processed foods, alcohol and caffeine so that you feel good going into the fast and don't send the body into a detoxing situation.
Generally, the worse your diet is, the more slowly and carefully you should prepare for a fast. And the longer the fast you plan on taking, the longer the preparation should be.
Even more important than preparing is the way you come off of a fast. "If you eat the wrong things after the FMD, you can end up in the hospital," says Wisinger. "The re-feeding process is really tricky, and it requires a lot of experience to get that right." The same is true coming off of a water fast and any other fast lasting longer than 24 hours.
"I think it was George Bernard Shaw who said, 'Every fool can fast,'" says Wisinger. "'Only a wise man knows how to break a fast.' And that's very true."
Sonia Wisinger, Wisinger Fasting, Nutrition & Wellbeing:
Valter Longo Foundation: