Intermittent Fasting Slows Aging, Fights Disease, Builds Muscle, and Burns Fat

By: Cat Ebeling, co-author of the best-sellers:  The Fat Burning KitchenThe Top 101 Foods that Fight Aging & The Diabetes Fix

The newest diet trend is NOT eating. That’s right. Intermittent Fasting. It certainly makes sense, given that our primal ancestors went through periods of not eating while searching for food, as well as periods of feasting when food was plentiful. Our bodies were made to adapt to that—not regularly timed, three meals a day, 7 days a week readily available food. So it makes biological sense to skip a meal or two occasionally.

Taking a break from eating has several proven dramatic health benefits including slowing down aging, increasing Human Growth Hormone for muscle growth, increasing insulin sensitivity, and overall fat burning.

In addition, IF has been shown to help fight cancer, disease, diabetes, and other serious diseases, according to this study reported in the American Journal of Clinical Nutrition. Additionally, according to other scientific studies, IF benefits extend to asthma, allergies, infectious diseases, rheumatoid arthritis, osteoarthritis, Tourette’s syndrome, cardiac arrhythmia’s, hot flashes from hormonal fluctuations, multiple sclerosis, atherosclerosis, Alzheimer’s and more.

Intermittent fasting can also increase energy, help with focus and clear thinking, and improve mood as well. Practicing IF helps reduce symptoms of depression. This study published in the Journal of Nutritional Health and Aging found a significant reduction in anger, tension, confusion and low mood in a group of older men who were practicing IF.

Researchers have also found that intermittent fasting lowers the risk of degenerative brain diseases like Alzheimer’s, dementia and even helps improve recovery from strokes. It is thought the fasting protects the neurons against various kinds of damaging stress.blank

During a period of intermittent fasting, the body switches its energy source from glucose (unless you are fully ‘fat-adapted’, to burning fat for energy. When we fast for a longer period of time, we use up all glucose stores and convert body fat to fatty acids or ketones. It is a way of helping to flip your ‘metabolic switch’ and help your body become better at being ‘fat adapted’.

A scientific review, published in the journal Obesity, shows that it is likely that intermittent fasting may be more healthful than other dieting strategies, as ketones put less stress on cells than the byproducts of other diets. In addition, IF helps the body become better and more efficient at utilizing fat for energy, especially if IF is done on a regular basis. It also helps the body switch back to fat burning if you have gotten off-track and carb heavy with your diet. It is, in essence a way to get back on track.

The point of intermittent fasting is that the periods of food deprivation allow your body to rest, renew and regenerate. Plenty of scientific studies on both animals and humans show that periodic fasting not only helps you lose weight but also increases your longevity. Caloric restriction through fasting also helps to turn on genes that repair DNA and cells. This adaptation of IF may allow certain cells to actually live longer, preserving the body’s energy, according to a study published in the journal, Cell Metabolism. This may also be part of the reason that fasting helps to extend longevity as well.

Scientists think that the IF acts as a form of healthy stress that revs up the cellular defenses against molecular damage. Fasting mice have been found to have higher levels of brain-derived neurotrophic factor (BDNF), which is a protein that prevents stressed neurons from dying. Low levels of BDNF have been tied to depression, anxiety, and dementia.

Fasting also ramps up autophagy, a kind of garbage-disposal system in cells that gets rid of damaged molecules, including ones that have been connected to Alzheimer’s, Parkinson’s and other neurological diseases.

Intermittent fasting has also been shown to reduce cancers resulting from oxidative damage, and to help maximize the positive effects of chemotherapy, while minimizing the negative effects of cancer treatment.

The question is—should you try it? Intermittent fasting obviously can be a powerful tool to maximize health, but it’s important to carefully weigh its effects. Intermittent fasting can last for a period of hours or even days, but generally it entails a brief fasting period of 12-24 hours. Most of us may already be fasting from dinner time to breakfast, and if you skip breakfast, you are fasting—provided you only drink black coffee, tea or water during your fast.

There are a few primary types of intermittent fasting to follow, and you can switch them around as much as you want—the point is to create episodic eating/fasting/eating similar to our hunter-gatherer ancestors. So, you don’t really need to follow any particular fast–just surprise your body every once in a while with 24 hours of little or no food.blank

One of the easiest ways to incorporate IF into your routine is to just skip breakfast. Ignore the old saying of “breakfast is the most important meal of the day”, and just drink black coffee, tea or water in the morning.

After a full night’s sleep, you wake up with the perfect hormonal terrain for burning fat. Low insulin and high glucagon levels make delaying your first meal an effective strategy for prolonging this fat-burning period.

Types of Intermittent Fasts

Skipping Meals–Every week or so, skip breakfast and don’t eat until lunchtime or dinner. Or just eat a late lunch and skip dinner and breakfast. Listening to your body and eating when your natural hunger occurs, instead of sticking to the meal clock and eating every morning, noon and night is a good way to readjust hunger.

Condensed Eating Window—One of the more popular and easier to follow IF routines is to condense your food intake into a set number of hours, usually about 8 hours. This generally means you eat an early dinner, and a late breakfast, much like the 16:8 plan. For sixteen hours you avoid eating, and eat only during a compressed time of 6-8 hours during the day.

24-hour Fast—Generally this works for most people by eating a normal dinner and then fasting until the following evening. Others can choose to extend the fast until the following morning. For many people, this can be a weekly or monthly routine.

Why Women Should Be More Cautious About Fasting

Fasting sounds like a terrific way to improve health and lose weight, right? Well it’s a little different for women and there’s a few things to consider, if you are a woman, before you jump headlong onto the fasting wagon. Some of the great health benefits do not extend to women.

We women have hormones that help to regulate our cycles and fertility. IF is a hormone stressor, so for men this creates an adaptive response that is positive for health. For women, IF can interfere with fertility and menstrual cycles. Because women’s bodies are meant to nourish and support a pregnancy, our bodies are extremely sensitive to calorie restriction.

Fasting affects the hypothalamus in the brain which can disrupt the gonadotropin-releasing hormone (GnRH), which is responsible for releasing Luteinizing Hormone, and Follicle Stimulating Hormone, both important for menstrual regularity and fertility.

When these hormones cannot communicate with the ovaries, you run the risk of irregular periods, infertility, poor bone health and other health effects.

Even if you are not planning on having children, fasting creates nutritional stress, which decreases fertility, and even decreases ovarian size.blank

Where IF improves insulin sensitivity in males, females don’t often see the same positive results. In fact, one study showed exactly the opposite results—glucose tolerance worsened. One study compared caloric restriction to intermittent calorie restriction in overweight and obese women. Both groups lost a similar amount of weight, but unfortunately, the intermittent restriction group lost significantly more lean body mass. This is muscle, the kind of body mass you want to keep.

Another looked at healthy men and women doing moderate intensity morning cycling either fasted (overnight) or fed (breakfast). Although both men and women displayed greater increases in VO2 max and resting muscle glycogen concentration in response to fasted cycling training, only men showed greater skeletal muscle adaptations when fasted. Women had better muscle adaptations when fed.

So what does this mean for women? IF can be beneficial, just be cautious if you are trying to have a baby, nursing a baby or have menstrual irregularities. Instead of aiming for the longest fast you can tolerate, aim for the shortest fast that gives results.

Fasting for women is good if:

• You have significant amounts of fat to lose.
• Your oncologist giving you the go-ahead to try using it to improve the effects of chemotherapy.
• Your neurologist giving you the go-ahead to try using it to improve brain function in the face of cognitive decline or dementia.

Be aware–fasting in an extreme or unhealthy way can be a symptom of an eating disorder.

Fasting for both men and women can have some major health benefits, especially done in a controlled and safe manner. Just be careful you don’t take it too far. Prolonged fasting has also been associated with:

• increased cholesterol
• pancreas damage
• worsened insulin function (which increases the risk of diabetes)
• irregular heartbeat, headaches and fainting
• slight reductions in athletic performance, exercise ability and muscle mass

Note: Fasting is not recommended for those who need a regular supply of nutrients for their health, including pregnant or breastfeeding women, or people with certain medical conditions. Possible side effects related to fasting include malnutrition, dehydration, disordered eating and even death in some cases. But serious risks are rare and usually related to prolonged fasting, not IF.

The Best Type of Intermittent Fasting…

Deciding to do Intermittent Fasting can be pretty scary, but there’s one method I trust more than the others…

In fact, this method of Intermittent Fasting has been shown to help people lose upwards of 7 pounds in the first 5 days, and some have lost 4 pounds OVERNIGHT, as well as boosting sex hormones for both men and women, improving your energy, skin, & brain function, and so much more.

The great thing is that the fat loss from THIS type of Intermittent Fasting is the most stubborn fat on your body – the fat you’ve tried to lose for years, but just won’t go away. But please keep in mind that this is so effective it’s only recommended you do it once, maybe twice, a week…

Click here to discover this powerful Intermittent Fasting method and lose up to 4 pounds overnight



About The Watchdog

Mike Geary has been a Certified Nutrition Specialist and Certified Personal Trainer for over 15 years now. He has been studying nutrition and exercise for almost 25 years, ever since being a young teenager. Mike is originally from Pennsylvania, but has fallen in love with mountain life and now resides in the picturesque mountains of Utah. Mike is an avid adventurist and when he’s not spending his time skiing, mountain biking, hiking, or paddleboarding on the lake, he has enjoyed skydiving, whitewater rafting, piloting an Italian fighter plane (seriously), scuba diving, heli-skiing, and traveling all around the world, enjoying learning about different cultures. At the age of 40, Mike now feels healthier, stronger, and more energetic than when he was 20... All because of a healthy lifestyle and great nutrition!

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  1. Greetings,
    I love all your blogs!
    We are on the same page… I’m going to forward clients to your site:)

  2. Thanks for this info! I’ve been hearing about how effective IF is but not how risky it can be for us women. Glad you share this post! 🙂

    • I was totally unaware about difference in health benefits of fasting for man & woman. Thanks for all these great informations

  3. most of the things that you say i knew not.thank for sharing this information with me

  4. I am most interested in ‘C’ ‘E’ ‘F’.

  5. Christopher Collins

    I agree totally with intermittent fasting hower question I have is what do you do if your taking medications and I believe that most or all should be taken with food. ‘What does and individual do in this situation.

    • 1. not all meds require food, and in fact some must be taken on an empty stomach. same with supplements. read the directions on each, and if nothing is mentioned on the label ask the doc when prescribed, or pharmacist when picking up a new RX.

      2. if food is required, then the 24 hour fast is out. but the 16/8 should work. if taken once a day you have an 8 hour eating window. if twice a day, take at the start and end of the 8 hour eating window, if 8 hours apart is allowed (and not 12 hours).

  6. IF is a complete disaster for me – I have IBS & if I do a 24 hour fast I get explosive diarrhoea; pains in my torso & shooting pains down my arms. Works fine for my husband.

  7. How are postmenopausal women affected? If your body isn’t in nurturing mode, do the effects mimic those of men or are they just minimized female effects?

    • That’s a good question that wasn’t addressed. Also since it’s talking about disrupting hormones, as a long post-menapousal woman who also uses bioidentical hormones I don’t see that it is a problem – I’ve done it a lot and find it to be the best! But I also don’t find it hard to go 16 hours without eating including overnight – as long as you keep carbs low! It also seems to help my digestive issues.

    • I have been intermittent fasting for about 2 months and it hasn’t bothered me I’m 73 and have thyroid issues but I find that going low carb helps to make the fast time go better. I fast 16 hours a day and 24 hours once a week. ?

  8. Is it okay to fast like 36 hours: skipping three whole meals?

  9. Christer Ståbis

    I am a male. Today is about the 7th day of fasting. I feel no fear. (I have done intermittent fasting even before, even if I didn’t knew anything about it before this autumn. It just happen to be so earlier now and then, due to mountain activities or just doing things at home and “forget” to eat.)
    This fasting I eat just a dinner every day. A few days I have ate breakfast. I drink water and tea. Green tea in the morning and red tea in the evening. Instead of cycling to my work about 2-3 days a week I cycled every day this week. (I got about 10 km to work, single way. So about 20 km per day.)
    I am astonished to see what happened to my weight ! I have lost several kg the last days ! (1 kg = 2,2 pounds.) I have steady dropped in weight this week. Don’t know the starting weight but about 80-81 kg, I guess. Two days ago my weight was 78 kg and yesterday 77 kg ! For a year ago my weight was about 84-85 kg. I started to loose weight when I quit eating bread and ice cream and started eating much vegetable.
    Today is the first day I feel any negative effect. I feel a mild dizzyness. Today I also feel for eating a bit more, which I will do. So I guess my body just tell me what to do.
    What I feel a little bit worried about is the possible release of toxins and what may happen to them. Maybe I am starting to feel some of those now (dizzyness)…?
    I will probably eat a little bit more from now on, but not much. I will see. I will go along with what my body feel.
    I hope this long message can be of any help for someone (that bothers to read it all :D).

  10. After I bought Mike Geary’s Truth About Abs program maybe a decade ago, he was all for eating 6 small meals a day, and said how that keeps metabolism active and some other health benefits. I would like to see what he feels about his previous thoughts on this in contrast to Intermittent Fasting.

    • I’m a night nurse so I sleep during the day and work all night 12 hour shifts. I have been IF before it was talked about. I don’t eat from 3am till 9 or 10pm. Found it helps with my gut health. I eat usually 1 meal and a snack between 10pm to 3am then stop. It has really helped my GERD. That’s my daily routine.

    • i think that theory about eating 6 small meals a day to keep the ‘fires burning’ has now been discarded. Fasting actually turns off the digestive track, giving it a rest, which has health benefits.

  11. I have read and I teach my patients that they only thing they can have when doing intermittent fasting is water… no coffee or tea. Coffee alone causes an increase in blood glucose, so how can this continue a fasted state? Black tea technically, should would have the same effect and herbal tea has herbs. Let’s add all of these have pesticide and or herbicide residue so your liver is working harder to detoxify them when one of the points of fasting is so the body can detoxify. Why would you add anything that needs detoxing? Stick with water.

    • Porque quase todas estas informações sobre saúde teem de estar em ingles? Estão a pensar que o português médio consegue traduzir ?Até apetece jogar a internete e o smartfone pela janela. Sejam simpáticos e pensem naqueles que não tiveram culpa da sua pouca instrução.!

    • so you’re saying that black coffee and unsweetened tea, both of which should have zero calories, breaks a fast? that’s not what i have read. both should not ‘turn on’ the digestive system during a fast.

  12. Ive read that nothing besides water w/ or w/out electrolytes will ‘wake up’ liver and stop IF…..

  13. My chiropractor has me doing the 16:8 IF. However, I’m not sure if this is a good idea for me as I have low blood pressure and had hypoglycemia at one time. Back then I was told I needed to eat tiny meals about every three hours. I’ve done the IF for a week now & GAINED 2 pounds. The chiropractor told me to eat less. I don’t know how i can eat less than 1/2 cup of fruit & 2 little turkey sausages for breakfast and two veggies & a little piece of meat for dinner, plus another little piece of fruit!

  14. When I was in my early twenties I had a particularly un-prosperous summer, bicycling twenty or more miles a day and eating only once in the early evening. This produced a curiously benign routine that resulted in the transition from nearly two hundred pounds to one sixty from early May to the end of June. At that age and given the consistent exercise, the effect was profoundly beneficial, with no apparent difficulties. More recently I have periodically engaged in eating in a six hour window every other day and significant walking each day, with roughly similar results, although using the regimen in much shorter spans. With apophagy and calorie restriction among the side benefits, the principal mechanism appears to be the attaining of at least thirty six hour of zero insulin stimulation, glycogen reserve exhaustion and the near complete shift to ketolysis – a hormonal reset. The effective timeframe is extended by exercise, with rule of thumb of a mile of walking roughly equivalent to an additional hour. The insulin receptors get a break to recover and lipid metabolism is routinely stimulated. It is essential to avoid carbohydrates of course, but also proteins, as they will, under such circumstances, be converted to sugars by the liver. In reality, trace minerals, maintaining plenty of ascorbate (vit C) intake along with extra hydration, with NO additional food during the fast, plus both calorie draw and stimulated circulation are the ticket. Some detox side effects have been noted by some. I have noticed second-morning urine darkening on occasion, presumably due to apophagy discharged through the kidneys – all the more important to maintain extra hydration (pure water only). Suggesting this regimen to diabetic friends, for instance, generally elicits horror, as their insulin-carbohydrate addiction syndrome becomes fully evident; at such a point we see that their bodies are auto-compromised much like a drug addict. Even so, and with considerations of medical supervision, I would bet that such cases, especially non-insulin-dependent, can be recovered. Fasting for longer than two days has been successful for some, although there is debate about overall effect on the body, along with considerations for individuals and special cases of obesity. Eating once daily in a narrow window and with some dietary restrictions (no corn syrup, minimal bread, etc), or eating once every other day seem to be excellent methods. For those who have difficulty or are medically not recommended, it would seem reasonable to work with a suitable doctor a regimen that can gradually expand the fasting window through careful coordination. In such cases there is a caveat that proteins, for instance, become an occult supply of glucose thereby compromising the objective of minimising insulin stimulation. No doubt there are other biochemical intricacies to the overall picture, but in general they seem to reduce to the common denominator of achieving thirty six or more hour effective fasting, natural detoxification and the hormonal reset. Beyond that, hydration…. hydration…. and remember to compensate for the genetic defect of no ascorbate production with a few grams of vitamin C. I prefer Bronson #149 for that purpose, as it supplies the C in a buffered form with the proper balance of calcium and magnesium. Also, when done for a period of time, fasting into once daily or better every other day becomes routine and the mind and body get sharper, never mind more lean. In a desperate moment of hunger, perhaps a tablespoon of hempseed nut (hemp hearts), but just once. Namaste, SKO

  15. IF can also increase risk of gallstones……………

  16. Would IF be contraindicated in Fatty Liver Cirrhosis patients, due to ketones processing through an already low functioning Liver?

  17. Jeremy Harrison-Roberts

    I couldn’t agree more. Last March I switched my eating plan in three ways: cutting carbs to no more than 20 grams daily, replacing “healthy low fat products” with high fat foods – meat, cheese, eggs, cream – and cutting out breakfast.

    Lunch consists of a large bowl of fruit (count the carbs therein as they can be high), with ample double cream. Evening meals would have high fat content & vegetables.

    I’ve always doubted those who claim they’re not hungry on certain regimes, but in all honesty, I’m not. Additionally, I have not counted calories & eat exactly what i want, as above. The result? I’m now 4 stones’ lighter.

  18. I have been following Brad’s Eat-Stop-Eat since his first edition came out many years ago and recommend it highly. At 78 I am now in better shape physically than wen I was in my 30’s. One great thing about the program is it’s flexibility. I find the 16-8 (skipping breakfast) the easiest for me, but the program is so flexible it allows most people to find a schedule that works well for them. I like the fact that I don’t have to give up any of my favorite foods abs still go to carnivals and summer fests and enjoy the food without guilt. Intermittent fasting may seem hard at first, but if you start out slow and work at, it won’t be long before it will seem natural and liberating. It is important that you read the book before you start and experiment with the times and duration’s to find what works best for you and Listen to your body.

  19. I am an 83 year old woman and IF has become a way of life for me. I am 5’8″ and am now 7 lbs less than my high school weight (which was 137). It is the only weight loss method that has allowed me to keep the weight off. As others have said, it is very easy to do and allows you to eat your favorite foods. Here is how I do it: 4 days a week I eat dinner at 5:30 or 6 PM and then breakfast at 9 AM. Then for 3 days (Mon, Wed, Fri) I eat no breakfast and eat lunch at noon. That makes a 5 or 6 hour window for eating 3 times a week and a 8 or 9 hour window 4 times a week. As others have said, see what works best for you. We are all unique.

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