Fasting diet and juice, benefits and risks, effect on blood sugar and weight loss
July 12 2018 by
Ray Sahelian, M.D.

It is possible that occasional short fasts are healthy to the body and can improve health and possibly improve longevity.

Fasting and immune system benefit
Fasting for as little as three days can regenerate the entire immune system, even in the elderly. Starving the body stimulates stem cells into producing new white blood cells, which fight off infection. Scientists at the University of Southern California say the discovery could be particularly beneficial for people suffering from damaged immune systems, such as cancer patients on chemotherapy. It could also help the elderly whose immune system becomes less effective as they age, making it harder for them to fight off even common diseases. The researchers say fasting "flips a regenerative switch" which prompts stem cells to create brand new white blood cells, essentially regenerating the entire immune system.

Better option than a total fast
Eating a very healthy diet, low in calories, is a better option in the long run. Eat more raw, fresh and organic fruits and vegetables, reduce dairy intake, reduce meat products, eat more whole grains, consume fish caught in the wild, drink more varieties of teas, drink fresh vegetables juice, add more herbs to your food, avoid or dramatically reduce sugar and baked goods, use some antioxidant supplements and herbs (there are many to choose from). Also, drink filtered water and wash your fruits and vegetables.

Fasting may benefit the heart
People who skip meals once or twice a month are less likely to be diagnosed with clogged arteries than those who do not regularly fast. When people take a break from eating a half a day or a day, it forces the body to dip into fat reserves to burn calories. It also keeps the body from being constantly exposed to sugar and having to make insulin to metabolize it. When people develop diabetes, insulin-producing cells become less sensitive to cues from eating, so fasting may provide brief rests that re-sensitize these cells and make them work better. However, fasting is not a good way for long term weight loss. Fasting resets the metabolic rate slowing it down to adjust to less food. This leads to the body to store calories as soon as a person resumes eating.

Occasional water-only fasts may lower your risk of heart disease and diabetes, according to new research presented at the 2011 annual scientific sessions of the American College of Cardiology in New Orleans. The study was conducted in Salt Lake City, where two-thirds of the residents are Mormons who fast once a month for 24 hours for religious purposes. In a previous study, the same team of researchers found that people who answered "yes" to the question "Do you abstain from food and drink for an extended time?" had a lower prevalence of coronary disease.

Fasting or caloric restriction - Alternate day fasting is one option
Cutting calories by fasting every other day may make cells less prone to becoming cancerous. Scientists at the University of California, Berkeley, found that when they put mice on a routine of alternate-day fasting, it reduced the rate at which the animals' body cells divided and proliferated. Because cancer begins when abnormal cells are allowed to divide and spread unchecked, this slowed-down cell division could theoretically reduce the risk of tumor development. However, it's too soon to draw that conclusion, since the study did not look at cancer incidence among the animals, said Dr. Marc Hellerstein, who led the research. The study, published in the May 2005 issue of the American Journal of Physiology, Endocrinology and Metabolism, adds to a growing body of evidence that links calorie cutting to both longer life and lower cancer risk in animals. Whether fasting could help people lower their cancer risk or prolong their lives is not yet known. But the encouraging finding from this study is that it didn't take substantial calorie deprivation to influence beneficial cellular changes. The mice fasted four days a week and allowed to eat as much as they wanted on non-fasting days. The net effect was a five-percent lower-than-normal calorie intake, which in humans would amount to eliminating about 100 calories per day. The impact of this modest calorie reduction on cell division was nearly as significant as what Hellerstein's team saw in a group of mice whose calorie intake was slashed by one third.
   There are a number of theories on why limiting food might make for a longer, healthier life. One idea is that slowing the rate of metabolism reduces the generation of oxygen free radicals. When it comes to cancer specifically, research has suggested that calorie cutting could be beneficial in a number of ways -- with reduced cell proliferation being one. Exactly why fasting or general calorie restriction might dampen cell proliferation is unclea. What the signal or signals are is unknown, but one possible player is insulin-like growth factor type 1 (IGF-1) -- a protein that helps spur cells to multiply and has been implicated in the cancer process. Previous animal research has shown that calorie restriction reduces blood levels of IGF-1. American Journal of Physiology, Endocrinology and Metabolism, May 2005. book on fasting

Alternate-day fasting may provide health benefits
Calorie restriction and alternate-day fasting are different forms of caloric restriction. In terms of diabetes risk, animal studies of alternate-day fasting find lower diabetes incidence and lower fasting glucose and insulin concentrations, effects that are comparable to those of calorie restriction. In terms of cardiovascular disease risk, animal alternate-day fasting data show lower total cholesterol and triacylglycerol concentrations, a lower heart rate, improved cardiac response to myocardial infarction, and lower blood pressure. In terms of cancer risk, there is no human evidence to date, yet animal studies found decreases in lymphoma incidence, longer survival after tumor inoculation, and lower rates of proliferation of several cell types.

Juice fasting
I'm not so sure juice fasting is healthy since it exposes the body to lots of fructose, particularly if the juice is mostly fruit.

Metabolic benefits
Turk J Med Sci. 2014. Possible metabolic impact of Ramadan fasting in healthy men. Insulin sensitivity and p3-cell function during Ramadan fasting in healthy male subjects have not been investigated so far. We assessed the changes of these and other metabolic parameters to judge the potential metabolic benefits of Ramadan fasting. Twenty-four healthy males of Turkish origin living in Germany, with normal glucose tolerance, participated in this study during Ramadan of 2009; 19 who completed fasting were analyzed. Blood was drawn at sunset after a period of fasting lasting approximately 15 h on days 0, 16, and 30 of Ramadan, as well as 7 and 28 days later. Insulin sensitivity (Homeostasis Model Assessment, HOMA), p3-cell function, and other parameters were assessed. Ramadan fasting was associated with a significant reduction (-) or increment (+) for the following variables: insulin sensitivity (-20%), β3-cell function (+10%), high-density lipoprotein cholesterol (-23%), low-density lipoprotein cholesterol (+14%), nonesterified fatty acids, resistin, adiponectin (+16%), and glucagon. C-peptide, insulin, leptin, triglyceride, and very low-density lipoprotein cholesterol concentrations were not significantly changed. Ramadan fasting is associated with transiently impaired insulin sensitivity, compensated for by an increased p3-cell function. However, the pattern of insulin resistance-mediating adipocytokines suggests a potentially beneficial metabolic effect of Ramadan fasting.

Fasting before chemotherapy
PLoS One. 2012. Fasting enhances the response of glioma to chemo- and radiotherapy.

Fasting for weight loss
Fasting may lead to short term weight loss but it is uncommon to keep the weight off permanently without making some permanent lifestyle changes.

Intermittent fasting (IF; severe restriction 1 d/week) facilitates weight loss and improves coronary heart disease (CHD) risk indicators. The degree to which weight loss can be enhanced if IF is combined with calorie restriction (CR) and liquid meals, remains unknown. Findings from this study suggest that IF combined with CR and liquid meals is an effective strategy to help obese women lose weight and lower CHD risk. Nutr J. 2012. Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women.

Fasting for toxin removal
There is no doubt that we are exposed to countless harmful substances in our environment - hormones, pollutants, pesticides, drugs, oxidants, toxins, and heavy metals. We are exposed to these toxins through food, water, air, and skin. And in many cases it is relatively easy to point the blame to these harmful substances for causing or aggravating certain diseases. For instance, it is clear that many inhaled pollutants can aggravate asthma symptoms. But, many people are eager to blame their symptoms to toxins even if there is no proof that they are the cause. For instance, toxins are certainly not the cause for the majority of cases of fatigue, yet some people who are tired all the time are ready to blame toxins for their condition. And then they undertake drastic steps - for instance a water or juice fast - which in some cases makes them feel even worse. And when they feel worse, they incorrectly think the reason is because toxins are being removed from their body. Most likely the reason is low caloric intake, low protein intake, muscle tissue breakdown, low glycogen stores in the liver, low blood sugar, etc.
   We probably all have toxins accumulated in our system. And what is the best way to deal with them? I believe undertaking several long term measures are a better approach than drastic short term steps (although perhaps a minority of those trying a drastic diet may notice some benefits such as mental clarity or a sense of wellbeing, others may get worse). For instance, rather than fasting for a few days, I prefer reducing caloric intake to perhaps 1000 or 1200 calories a day over a period of 2 to 3 weeks. I am not convinced that any of the so called drastic "detox diets" that recommend a strict regimen of lemon juice, olive oil, apple cider vinegar, cayenne, etc, etc, are beneficial. Through all my years of medical education, I have come to realize that the body does not like going off balance too much and for too long. Our body tries to maintain homeostasis, a balanced state where everything is functioning properly. Fasting, or these drastic detox regimens alter this homeostasis, often in a harmful way. Liver glycogen stores are depleted, alterations occur in the mineral and electrolyte balance in the blood, muscle and bone tissue start breaking down, changes occur in the acid base balance, alterations occur in the fatty acid composition of cells, and immune function may be impaired. Having said this, I think early research shows that going without food for half a day or a day each month could provide health benefits.

J Cereb Blood Flow Metab. 2014 Feb 19. Intermittent fasting attenuates increases in neurogenesis after ischemia and reperfusion and improves recovery. Intermittent fasting (IF) is neuroprotective across a range of insults, but the question of whether extending the interval between meals alters neurogenesis after ischemia remains unexplored. We therefore measured cell proliferation, cell death, and neurogenesis after transient middle cerebral artery occlusion (MCAO) or sham surgery (SHAM) in mice fed ad libitum (AL) or maintained on IF for 3 months. IF was associated with twofold reductions in circulating levels of the adipocyte cytokine leptin in intact mice, but also prevented further reductions in leptin after MCAO. IF/MCAO mice also exhibit infarct volumes that were less than half those of AL/MCAO mice. We observed a 30% increase in basal cell proliferation in the hippocampus and subventricular zone (SVZ) in IF/SHAM, relative to AL/SHAM mice. However, cell proliferation after MCAO was limited in IF mice, which showed twofold increases in cell proliferation relative to IF/SHAM, whereas AL/MCAO mice exhibit fivefold increases relative to AL/SHAM. Attenuation of stroke-induced neurogenesis was correlated with reductions in cell death, with AL/MCAO mice exhibiting twice the number of dying cells relative to IF/MCAO mice. These observations indicate that IF protects against neurological damage in ischemic stroke, with circulating leptin as one possible mediator.

Mediterranean diet and extended fasting's influence on changing the intestinal microflora, immunoglobulin A secretion and clinical outcome in patients with rheumatoid arthritis and fibromyalgia: an observational study.
BMC Complement Altern Med. 2005
Alterations in the intestinal bacterial flora are believed to be contributing factors to many chronic inflammatory and degenerative diseases including rheumatic diseases. While microbiological fecal culture analysis is now increasingly used, little is known about the relationship of changes in intestinal flora, dietary patterns and clinical outcome in specific diseases. To clarify the role of microbiological culture analysis we aimed to evaluate whether in patients with rheumatoid arthritis (RA) or fibromyalgia (FM) a Mediterranean diet or an 8-day fasting period are associated with changes in fecal flora and whether changes in fecal flora are associated with clinical outcome. We found no significant changes in the fecal bacterial counts following the two dietary interventions within and between groups, nor were significant differences found in the analysis of sIgA and stool ph. Clinical improvement at the end of the hospital stay tended to be greater in fasting vs. non- fasting patients with RA. Clinical outcome was not related to alterations in the intestinal flora. Neither Mediterranean diet nor fasting treatments affect the microbiologically assessed intestinal flora and sIgA levels in patients with RA and FM. The impact of dietary interventions on the human intestinal flora and the role of the fecal flora in rheumatic diseases have to be clarified with newer molecular analysis techniques. The potential benefit of fasting treatment in RA and FM should be further tested in randomised trials.

Incorporation of fasting therapy in an integrative medicine ward: evaluation of outcome, safety, and effects on lifestyle adherence in a large prospective cohort study.
J Altern Complement Med. 2005.
This was a prospective observational study with consecutive inpatients over 13 years. Inclusion and exclusion criteria for fasting therapy were checked by treating physicians and recommendations given. After receiving full information patients decided whether they would participate in fasting. Outcomes were assessed on admission, at discharge, and 3 and 6 months after discharge. Subjects were newly admitted inpatients with chronic internal diseases and chronic pain syndromes, with lengths of hospital stay of >3 days. All patients received intensive integrative treatments including Mind/Body Medicine, acupuncture, nutritional/lifestyle education, and hydrotherapy. Fasting patients participated in a 7-day juice fast (intake <350 kcal/day) with accompanying bowel cleansing, 2 pre fasting relief days, and 3 days with stepwise reintroduction of food. Outcomes were assessed based on rate of participation in fasting, severity of main complaint, quality of life, safety, lifestyle adherence to recommendations given (relaxation, diet, exercise). Of 2121 patients with complete discharge questionnaires, 952 patients participated in fasting, 873 had a normocaloric vegetarian diet, and 296 patients had other diets and were excluded. Response rates were 71% and 56% at 3- and 6-month follow-up. The main disease-related complaint at discharge was significantly greater improved in fasters versus nonfasters. Patient QOL increased significantly and comparably from baseline to discharge in both groups. Fasting was well tolerated and no serious fasting-related adverse effects were reported. In all, 743 (78%) of fasting patients reported improvement of their health through fasting. Descriptors of lifestyle adherence showed higher levels of related activities in the 3 and 6 months of follow-up. Fasting can safely and successfully be implemented in an inpatient integrative medicine concept and is perceived as a health-promoting method by the majority of patients. Potential effects on disease-related complaints and lifestyle adherence should be further evaluated in randomized trials.

Q. My girlfriend is really pushing this fasting program for us to try. What do you think?

Physiological Benefits
Fasting can be thought of as a period of profound rest, during which time your body is free to rapidly undertake a wide variety of beneficial physiological activities, some of which are described below.

1. Neuroadaptation
Fasting helps your taste sensors adapt to a low salt intake. By allowing your body to “neuroadapt” to low salt food, fasting rapidly facilitates the adoption of a health- promoting diet. This process of neuroadaptation appears to take place more rapidly during fasting than merely eating a low salt diet.
   Comments: Probably true, and the same can be said for sugar and sweets.

2. Enzymatic Recalibration
During fasting your body induces enzymatic changes that can affect numerous systems ranging from detoxification of endogenous and exogenous substances to the mobilization of fat, glycogen and protein reserves. These changes seem to persist after the fasting process, which may explain some of the dramatic clinical changes seen in patients after fasting.
   Comments: Probably true, however I do not know if some of the changes, in addition to having benefits, could also cause harm.

3. Weight Loss
Although fasting is not generally recommended as a primary weight loss strategy, weight loss is a predictable consequence of fasting. Most people average a loss of approximately one pound per day over the course of a fast. (When weight loss is your primary concern, a health- promoting diet coupled with exercise is usually your best approach.)
   Comments: Most people gain back the weight after they resume consumption of food.

4. Detoxification
Fasting is generally thought of as a tool to facilitate detoxification, promoting the mobilization and elimination of endogenous substances such as cholesterol and uric acid and exogenous substances such as dioxin, PCBs, and other toxic chemical residue.
   Comments: Perhaps, but could such rapid elimination cause harm to the body?

5. Insulin Resistance
Fasting appears to have a profound effect on insulin resistance, which is thought to be intimately involved with diabetes and high blood pressure. When your body produces adequate insulin, but it is ineffective due to resistance at the cells in the liver and elsewhere, your blood sugar levels rise. This can lead to serious clinical consequences. Fortunately, after a period of fasting, this problem is often dramatically improved.
   Comments: Probably true, but could the problem return once food is consumed again at a normal rate?

6. Natriuresis
Water-only fasting induces a powerful natriuretic effect, which allows the body to eliminate excess sodium and water from your body. This process allows for the resolution of chronic problems with edema and helps reduce the increased blood volume associated with high blood pressure.
   Comments: Maybe but it is not a long term solution.

7. Reducing Gut Leakage
When chronic inflammation involves the intestinal mucosa, a condition arises whereby small particles of incompletely digested foods can be absorbed into the blood stream. This introduction of foreign peptide molecules to the blood stream may stimulate an immunological cascade of effects collectively known as gut leakage. In genetically vulnerable individuals, gut leakage may be associated with the aggravation of numerous clinical entities including arthritis, colitis, asthma, allergies, and fatigue.
   Comments: It may help the intestinal tract to give it some rest.

8. Sympathictonia
Hypersympathictonia (increased tone of the sympathetic nervous system) is thought to be associated with many problems ranging from digestive disturbances to anxiety disorders. Fasting appears to have a profound normalizing effect on the overall tone of the autonomic nervous system. In all there are many mechanisms through which fasting may be having its profound effect.

   Comments: Perhaps, but it is only a temporary solution.

Q. "I'm starting a detox program to clear out toxins from my body," said a friend. "What's your opinion?"
   A. Many patients ask my opinion on "detox diets." Others have asked me about "liver or colon cleansing," or fasting. I know many people who have tried various "cleansing" methods including olive oil/lemon juice programs, colon irrigation, water and juice fasts, etc. I even came across some infomercials promoting herbal tablets that supposedly cleanse and rid the body of toxins. Do any of these work? And besides, what do people really mean when they use the words "detox" or "cleanse?" Many people who suffer from depression, fatigue, anxiety, allergies, digestive symptoms, headache, vague aches and pains, etc, think that these symptoms are due to accumulated toxins in their body. Are they right, or are they misdiagnosing the causation of their symptoms?

Q. My wife and I love your site and info. We would like your opinion about something. We just read a book which mentions a cleansing diet consisting of:

2 Tbsp. lemon or lime juice (organic)
2 Tbsp. genuine, pure, organic maple syrup
1/10 tsp. cayenne pepper
10-12 oz. purified water

The book states this cleansing diet helps purify the liver and:

-helps dissolve and eliminate toxins and congestion.
-helps cleanse the kidneys and digestive system.
-helps purify the glands and cells
-helps eliminate unusable waste and hardened material in the joints and muscles.
What do you think?