Intermittent fasting has been around since humans first roamed the earth and now it’s a new “secret” weapon for improved health and weight loss.
Wikipedia defines intermittent fasting this way:
Intermittent fasting (IF) is an umbrella term for various diets that cycle between a period of fasting and non-fasting. Intermittent fasting can be used along with calorie restriction for weight loss.
It has been long believed that a low-calorie diet or “calorie restriction” is very healthy and good for extending life as long as you continue to take in a balanced, nutrient-dense diet. Calorie restriction without malnutrition has been shown to result in longer maintenance of youthful health and decelerate the biological aging process in yeast, fish, rodents, and dogs. This is the periodic fasting method we discussed earlier. We do not want to confuse this with “dieting” in which we restrict calories over a period of weeks, months or years from an already malnourished body.
Many believe intermittent fasting can increase lifespan in humans. In addition to periodic fasting, the window of time in which we consume our calories has an important impact. If you recall, time restricted methods of fasting like The 8 Hour Diet, allows eating as much as you want for eight hours per day and abstaining from food entirely for the remaining sixteen. The basic principle here is that you are giving your body a much-needed rest two thirds of the time. In cultures known for their longevity, people take their last meal of the day well before the sunset and then “break the fast” after sunrise. There is mounting evidence that this plays an important role regarding weight management, longevity and overall wellness.
Proven Health Benefits of Intermittent Fasting
Research shows that intermittent fasting helps extend life, regulate blood glucose, manage cholesterol, burn fat and more. The benefits of intermittent fasting have been well-documented to help people look better, feel better, control weight, live healthier and longer.
Intermittent Fasting Reduces:
- body fat and weight
- blood lipids (triglycerides and LDL cholesterol)
- blood pressure
- risk of cancer
- oxidative stress
Intermittent Fasting Increases:
- fat burning
- metabolic rate
- cellular repair (autophagy)
- growth hormone release
Intermittent Fasting Improves:
- appetite control (through changes in ghrelin)
- blood sugar
- cardiovascular function
- effectiveness of chemotherapy (allows for higher doses more frequently)
Mark Mattson of the National Institute on Aging, has researched the health benefits of intermittent fasting and the benefits of calorie restriction. Mattson concludes that there are several theories to explain why intermittent fasting is so effective.
“The one that we’ve studied a lot, and designed experiments to test, is the hypothesis that during the fasting period, cells are under a mild stress, and they respond to the stress adaptively by enhancing their ability to cope with stress and, maybe, to resist disease. There is considerable similarity between how cells respond to the stress of exercise and how cells respond to intermittent fasting.”
So, in the same way our bodies respond by building muscle when stressed by exercise, stressing our bodies during a fast causes our cells to respond in a way that may help ward off disease. What Dr. Mattson is describing is a bodily process called hormesis. Hormesis is the body’s response to low exposures of toxins and other events that cause stress, such as strenuous exercise. Apparently, short-term fasting causes a hormetic response as well.
Fasting Controls Weight and Improves Health Markers
Intermittent fasting helps us lose weight and maintain ideal weight without slowing our metabolism. By creating a calorie deficit of 1500-2000 calories per day (depending on your current diet) you can obviously lose weight but because you are losing the weight over brief periods of calorie reduction you are not causing your metabolism to slow. This is a very important aspect of intermittent fasting.
Here are articles and studies expounding upon the benefits of Intermittent Fasting
Here is a study confirming fasting to be an effective method of losing weight and improving health markers, many others can be found in the appendix.
The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women.
The goal of this study should be of interest to us all. It was designed to compare intermittent fasting with Continual Calorie Restriction (typical low calorie diet) and tested a very wide variety of health markers including improvements in cholesterol (LDL and HDL), triglycerides, blood sugar, blood pressure, sex hormones, inflammation (C-reactive protein) etc. Here we see both calorie restriction and intermittent fasting are shown to improve a wide variety of factors that affect our overall wellness. And typically, it is believed that the compliance rate is higher with intermittent fasting.
The study concluded that intermittent fasting of two days per week compares favorably with a low calorie diet of every day and was more beneficial in improvements with insulin and insulin resistance.
RESULTS: Last observation carried forward analysis showed that IER and CER are equally effective for weight loss: mean (95 percent confidence interval) weight change for IER was -6.4 (-7.9 to -4.8) kg vs -5.6 (-6.9 to -4.4) kg for CER (P-value for difference between groups = 0.4). Both groups experienced comparable reductions in leptin, free androgen index, high-sensitivity C-reactive protein, total and LDL cholesterol, triglycerides, blood pressure and increases in sex hormone binding globulin, IGF binding proteins 1 and 2. Reductions in fasting insulin and insulin resistance were modest in both groups, but greater with IER than with CER; difference between groups for fasting insulin was -1.2 (-1.4 to -1.0) μU ml(-1) and for insulin resistance was -1.2 (-1.5 to -1.0) μU mmol(-1) l(-1) (both P = 0.04).
CONCLUSION: IER is as effective as CER with regard to weight loss, insulin sensitivity and other health biomarkers, and may be offered as an alternative equivalent to CER for weight loss and reducing disease risk.
Fasting Increases Human Growth Hormone and Lifespan
Routine periodic fasting is good for your health, and your heart, study suggests
Recent research conducted by Dr. Benjamin D. Horne, PhD, MPH, director of cardiovascular and genetic epidemiology at the Intermountain Medical Center Heart Institute, showed that fasting was responsible for an incredible 2,000 percent increase in human growth hormone in men and 1,300 percent in women. The human growth hormone stimulates growth, cell reproduction and regeneration, has been linked to longevity, and is often referred to as “the fitness hormone.” It promotes muscle growth and boosts fat loss by increasing metabolism.
Additionally, the study concluded that there was a benefit to cholesterol levels as well:
Unlike the earlier research by the team, this new research recorded reactions in the body’s biological mechanisms during the fasting period. The participants’ low-density lipoprotein cholesterol (LDL-C, the “bad” cholesterol) and high-density lipoprotein cholesterol (HDL-C, the “good” cholesterol) both increased (by fourteen percent and six percent, respectively) raising their total cholesterol – and catching the researchers by surprise.
“Fasting causes hunger or stress. In response, the body releases more cholesterol, allowing it to utilize fat as a source of fuel, instead of glucose. This decreases the number of fat cells in the body,” says Dr. Horne. “This is important because the fewer fat cells a body has, the less likely it will experience insulin resistance, or diabetes.”
Fasting Reduces Incidence of Inflammation
In a recent study of overweight adults with moderate asthma participants lost eight percent of their body weight by cutting their calorie intake by eighty percent on alternate days for eight weeks. In addition, markers of oxidative stress and inflammation decreased, and asthma-related symptoms improved, along with several other quality-of-life indicators as is examined in the following article.
Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma.
Even more astonishing, Mark Mattson and his colleagues compared the effects of intermittent fasting against calorie restriction for weight loss, insulin sensitivity and other metabolic disease risk markers. Published in the International Journal of Obesity in 2011, this study found that intermittent fasting was just as effective as calorie restriction for improving all these issues, and slightly better for reducing insulin resistance. According to the authors:
Both groups experienced comparable reductions in leptin, free androgen index, high-sensitivity C-reactive protein, total and LDL cholesterol, triglycerides, blood pressure and increases in sex hormone binding globulin, IGF binding proteins 1 and 2. Reductions in fasting insulin and insulin resistance were modest in both groups, but greater with IER [intermittent fasting] than with CER [continuous energy restriction].
Fasting for Diabetics
I am constantly being asked the question; Can diabetics benefit from intermittent fasting? The following study shows the benefits of intermittent fasting for diabetes. There are several others in the appendix, but the short answer is yes, absolutely diabetes can benefit greatly from intermittent fasting. With any medical condition (and especially for diabetics) be sure to consult your personal physician before trying any diet or exercise regimen. Losing weight (regardless of the method used) is one of the best things anyone who is diabetic can do to lower their blood sugar.
Intermittent Blasting for diabetics is a little tricky because greatly reducing calories on your Blast days will likely result in lower blood sugar. So you must monitor your blood sugar levels very closely. For this reason, I would recommend starting slower, perhaps just Blast over a period of one or two meals. Provided that goes well, work up to where you are Blasting for an entire day and then two days.
The effect of short periods of caloric restriction on weight loss and glycemic control in type 2 diabetes.
Two groups who utilized an intermittent fasting regimen achieved greater weight loss and improved blood sugar compared with participants on a traditional diet of 1500-1800 calories per day.
Periodic VLCDs (Intermittent Very Low Calorie Diet) improved weight loss in diabetic subjects. A regimen with intermittent 5-day VLCD therapy seemed particularly promising, because more subjects in this group attained a normal HbA1c. Moreover, the glucose response to a 3-week period of diet therapy predicted glycemic response at 20 weeks, and it was a better predictor of the 20-week response than initial or overall weight loss.
Fasting Has Anti-Cancer Properties
Fasts have been shown to inhibit and reverse cancer growth. It has been shown to “consistently improve survival” of animals in the lab and in human trials. Fasting could help combat cancer and boost the effectiveness of cancer treatments.
One study found that fasting slowed the growth and spread of tumors and cured some cancers when combined with chemotherapy.
It is hoped that this discovery will prompt the development of more effective treatment plans and further research is now under way. The latest investigation, published in the journal, Science Translational Medicine, found that tumor cells responded differently to the stress of fasting compared to normal cells. Instead of entering a dormant state similar to hibernation, the cells kept growing and dividing, in the end destroying themselves.
In the article referenced below lead researcher Professor Valter Longo from the University of Southern California says, “the combination of fasting cycles plus chemotherapy was either more or much more effective than chemo alone,” and “The cell is, in fact, committing cellular suicide. What we’re seeing is that the cancer cell tries to compensate for the lack of all these things missing in the blood after fasting. It may be trying to replace them, but it can’t.” Professor Longo and his team looked at the impact fasting had on breast, urinary tract and ovarian cancers in mice. Fasting without chemotherapy was shown to slow the growth of breast cancer, melanoma skin cancer, glioma brain cancer and neuroblastoma – a cancer that forms in the nerve tissue. Scientists found tumor cells responded differently to the stress of fasting compared to normal cells. In every case, combining fasting with chemotherapy made the cancer treatment more effective. Multiple cycles of fasting combined with chemotherapy cured 20 percent of those with a highly aggressive form of cancer while 40 percent with a limited spread of the same cancer were cured. None of the mice survived if they were treated with chemotherapy alone.”
Professor Longo added: “A way to beat cancer cells may not be to try to find drugs that kill them specifically, but to confuse them by generating extreme environments, such as fasting, that only normal cells can quickly respond to.”
Dr. David Jockers Interviewed in the Documentary, The Truth About Cancer
I am a big fan of intermittent fasting. It’s something I do every day and I think it’s a critical piece of a cancer-killing diet. So, for myself, you know really when we break down fasting I want all our readers to understand this. I look at a building phase and a cleansing phase. OK, our building phase is the time between our first meal of the day and our last meal of the day. So the typical American might eat at 8 A.M. and finish eating at 8 P.M. That’s about a twelve- hour building phase, and the cleansing phase would be the time from our last meal to our first meal. That’s like a 1-to-1 ratio. In our society, we’ve got so much toxicity that it’s that much more important that we have a greater cleansing phase than building phase. I like to have anywhere from a 16-to-18 hours, and sometimes even a 24- hour cleansing phase on a regular basis.…Intermittent fasting is a very, very powerful strategy that’s been shown to improve brain function, improve lean body tissue so your percentage of muscles to body fat is higher and it’s been shown to improve almost every aspect of your health. And so very, very profound when it comes to killing cancer cells in your body too.
Fasting and cancer treatment in humans: A case series report
The six patients who underwent chemotherapy with or without fasting reported a reduction in fatigue, weakness, and gastrointestinal side effects while fasting. In those patients whose cancer progression could be assessed, fasting did not prevent the chemotherapy-induced reduction of tumor volume or tumor markers. Although the 10 cases presented here suggest that fasting in combination with chemotherapy is feasible, safe, and has the potential to ameliorate side effects caused by chemotherapies, they are not meant to establish practice guidelines for patients undergoing chemotherapy.
Fasting Is Good for the Heart
Intermittent Fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women
This study demonstrates Intermittent Fasting contributes to improvements in a wide variety of health markers specific to heart health.
Sixty participants were measured for fat mass and fat free mass by dual energy X-ray absorptiometry (DXA), blood samples were collected, plasma total cholesterol, direct LDL cholesterol, HDL cholesterol, and triglyceride concentrations as well as fasting plasma glucose were measured in duplicate. Insulin, C-reactive protein (CRP), homocysteine, adiponectin, and leptin were also assessed in duplicate. All of these measurements were taken at week 1, 3, and 10. And blood pressure and heart rate were measured in triplicate each week using a digital automatic blood pressure/heart rate monitor. In other words, these participants were studied very closely.
The 10-week trial consisted of two dietary phases: 1) a 2-week baseline weight maintenance period, and 2) an 8-week weight loss period. During the weight loss period participants consumed 30% of their calorie needs six days per week and consumed only 120 calories one day per week.
The results were amazing and what I found most interesting is that across the board the metrics were better with the participants who consumed their calories from liquid rather than solid food.
Body weight decreased more (P = 0.04) in the IFCR-L group (3.9 ± 1.4 kg) versus the IFCR-F group (2.5 ± 0.6 kg). Fat mass decreased similarly (P < 0.0001) in the IFCR-L and IFCR-F groups (2.8 ± 1.2 kg and 1.9 ± 0.7 kg, respectively). Visceral fat was reduced (P < 0.001) by IFCR-L (0.7 ± 0.5 kg) and IFCR-F (0.3 ± 0.5 kg) diets. Reductions in total and LDL cholesterol levels were greater (P = 0.04) in the IFCR-L (19 ± 10 percent; 20 ± 9percent, respectively) versus the IFCR-F group (8 ± 3 percent; 7 ± 4 percent, respectively). LDL peak particle size increased (P < 0.01), while heart rate, glucose, insulin, and homocysteine decreased (P < 0.05), in the IFCR-L group only.
CONCLUSION: These findings suggest that IF combined with CR and liquid meals is an effective strategy to help obese women lose weight and lower CHD risk.
Fasting Improves General Health
I always say “give the body time to rest and good things happen”. Here are several studies that show how fasting intermittently improves a wide variety of health markers.
Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardio protection in obese adults.
In this study, sixteen obese subjects (twelve women and four men) completed a 10-week trial of alternate- day fasting. For this study, alternate day fasting is defined as a caloric reduction of 25 percent on fasting days. Body weight decreased, percentage of body fat decreased, total cholesterol, LDL (bad) cholesterol, triglyceride levels and systolic blood pressure all decreased.
The rate of weight loss remained constant during controlled food intake (0.67 +/- 0.1 kg/wk) and self-selected food intake phases (0.68 +/- 0.1 kg/wk). Body weight decreased (P < 0.001) by 5.6 +/- 1.0 kg (5.8 +/- 1.1percent) after 8 wk of diet. Percentage body fat decreased (P < 0.01) from 45 +/- 2percent to 42 +/- 2percent. Total cholesterol, LDL cholesterol, and triacylglycerol concentrations decreased (P < 0.01) by 21 +/- 4percent, 25 +/- 10percent, and 32 +/- 6percent, respectively, after 8 wk of ADF, whereas HDL cholesterol remained unchanged. Systolic blood pressure decreased (P < 0.05) from 124 +/- 5 to 116 +/- 3 mm Hg.
CONCLUSION: These findings suggest that ADF is a viable diet option to help obese individuals lose weight and decrease CAD risk.
Challenging Oneself Intermittently to Improve Health
To survive and reproduce, our ancestors spent most of their waking hours working to find food, either by ‘grazing’ on plants or by hunting animals. In many instances, the food supply was very limited and so there was a survival advantage for those who could tolerate and adapt to periods of food deprivation. One such adaptation is the metabolic shift from the use of glycogen stores in liver and muscle cells, to the mobilization of fatty acids in adipose cells and their conversion to ketones, an alternative cellular energy substrate (Longo and Mattson, 2014). Another interesting adaptation suggested by studies of animal models, is that cognitive function and stress resistance improve in response to intermittent fasting (Wan et al., 2003; Ahmet et al., 2005; Mattson, 2012a; Marosi and Mattson, 2014). Similarly, endurance running, such as is required to chase and kill a deer (Zimmer, 2004), not only strengthens the muscles and heart, but also improves brain function (Ahlskog et al., 2011; Mattson, 2012b; (Voss et al., 2013).
Intermittent Fasting Modulation of the Diabetic Syndrome in Streptozotocin-Injected Rats
Over thirty days, groups of 5-6 control or STZ rats were allowed free food access, starved overnight, or exposed to a restricted food supply comparable to that ingested by the intermittently-fasting animals. Intermittent fasting improved glucose tolerance, increased plasma insulin, and lowered Homeostatis Model Assessment index. Caloric restriction failed to cause such beneficial effects.
A periodic diet that mimics fasting promotes multi-system regeneration, enhanced cognitive performance and health span.
We show that alternating PF and nutrient-rich medium extended yeast lifespan independently of established pro-longevity genes. In mice, four days of a diet that mimics fasting (FMD), developed to minimize the burden of PF, decreased the size of multiple organs/systems; an effect followed upon re-feeding by an elevated number of progenitor and stem cells and regeneration. Bi-monthly FMD cycles started at middle age extended longevity, lowered visceral fat, reduced cancer incidence and skin lesions, rejuvenated the immune system, and retarded bone mineral density loss. In old mice, FMD cycles promoted hippocampal neurogenesis, lowered IGF-1 levels and PKA activity, elevated NeuroD1, and improved cognitive performance. In a pilot clinical trial, three FMD cycles decreased risk factors/biomarkers for aging, diabetes, cardiovascular disease and cancer without major adverse effects, providing support for the use of FMDs to promote health span.
Fasting: Molecular Mechanisms and Clinical Applications
Based on the existing evidence from animal and human studies described, we conclude that there is great potential for lifestyles that incorporate periodic fasting during adult life to promote optimal health and reduce the risk of many chronic diseases, particularly for those who are overweight and sedentary. Animal studies have documented robust and replicable effects of fasting on health indicators including greater insulin sensitivity, and reduced levels of blood pressure, body fat, IGF-I, insulin, glucose, atherogenic lipids and inflammation. Fasting regimens can ameliorate disease processes and improve functional outcome in animal models of disorders that include myocardial infarction, diabetes, stroke, AD and PD. One general mechanism of action of fasting is that it triggers adaptive cellular stress responses, which result in an enhanced ability to cope with more severe stress and counteract disease processes. In addition, by protecting cells from DNA damage, suppressing cell growth and enhancing apoptosis of damaged cells, fasting could retard and/or prevent the formation and growth of cancers.
There is much more research to support the idea that a variety of fasting regimens are beneficial. I encourage you to turn to the Appendix and look into some of the research that has been done in this area. It is both extensive and compelling.
Conclusions – Fasting is Nature’s Way of Maintaining Ideal Weight and Healing
Through my research and personal experience with the benefits of fasting I have discovered some key concepts:
- The body is designed to heal itself and is constantly working to reach a state of homeostasis. Fasting can greatly assist the body in healing by focusing its energy on repairing and restoration rather than digestion.
- Fasting is a natural part of life and one that is required for a longer, healthier life.
- Intermittent fasting may be as effective as long-term fasting and is less difficult to implement and maintain.
- It’s easier for most people to restrict their eating intermittently than to decrease their calorie intake on a consistent, ongoing basis.
- Proper nutrition is a key element in fasting. According to Dr. Stephen Freedland, Associate Professor of Urology and Pathology at the Duke University Medical Center, “undernutrition without malnutrition is the only experimental approach that consistently improves survival in animals with cancer.”
Also see articles and studies at https://www.fastblast.com/research/