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Fasting regimens may be key in treating type 2 diabetes


Fasting regimens have gained popularity as a technique for reducing weight and obesity. This strategy may improve insulin sensitivity in patients with insulin resistance and diabetes.

Fasting regimens have gained popularity as a technique for reducing weight and obesity.

This strategy may improve insulin sensitivity in patients with insulin resistance and diabetes.

A variety of fasting protocols have been proposed, including:

Intra-day fasting (e.g., no caloric intake 14 to 16 hours each day) or intermittent daily fasting (e.g., no caloric intake for 24 consecutive hours twice per week)

Partial fasting (also known as the warrior diet, e.g., includes minimal caloric intake for 20 consecutive hours followed by a single, large meal in the evening)

Alternate daily fasting (e.g., little or no caloric intake every other day followed by “normal” caloric consumption on feeding days-consumption on feeding days typically ranges from 1500 to 2400 calories and on fasting days ranges from 0 to 600 calories)

These protocols may result in more or less food craving, weight loss, and tolerability for specific people.1

Previously from Dr. Chous: Importance of adherence and follow-up in patients with diabetic retinopathy

Fasting works

The health benefits of caloric restriction in general and fasting regimens in particular have been demonstrated in numerous animal models and observational studies of human populations. There remains uncertainty as to whether the benefits apply to humans over extended periods.

A randomized controlled clinical trial of obese subjects who are exposed to continuous vs. intermittent calorie restriction is now underway. This study will give us insight into obesity-related metabolic gene expression and inflammatory markers.2


Over the last year, I have discussed alternate daily fasting (ADF) with many of my patients who have type 2 diabetes (T2DM). I began doing this after an optometric colleague suggested I check out a series of YouTube videos posted by Canadian nephrologist Jason Fung.

Fung’s premise is that most pharmacologic strategies for treating type 2 diabetes invariably result in disease progression, comorbidities and mortality, and never facilitate disease remission because they increase insulin levels and associated visceral adiposity (abdominal fat).

Weight-loss surgeries, extreme carbohydrate restriction, and/or fasting regimens often do result in remission of T2DM-though they are seldom used.

I’d like to report on my experience with ADF in one specific patient who experienced phenomenal results.

Related: Worldwide diabetes epidemic approaches half a billion

Patient needs help

P.K. is a 52-year-old male who was diagnosed with T2DM in 2013. His baseline HbA1Cwas 7.2 percent, and he was started on metformin by his primary-care practitioner (PCP), which lowered the A1C to 6.4 percent.

After 14 months, P.K.’s A1C rose to 8 percent and he was started on basal insulin therapy (Lantus (insulin glargine, Sanofi)-100 units daily), which dropped his A1C back to 7 percent.

Before starting insulin, P.K. weighed 230 lbs. (BMI=32.1 Kg/M2). One-year later, he weighed 250 lbs. (BMI=34.9).

When I examined him for the first time last year, he had no evidence of diabetic retinopathy, no history of cardiovascular (CV) disease, his blood pressure measured 130/88 on lisinopril (Zestril, AstraZeneca) and metoprolol (Toprol-XL, AstraZeneca), his blood lipids were well-controlled with LDL-C at 74 ng/ml on Lipitor (atorvaststain, Pfizer) and he reported occasional hypoglycemia.

When I specifically asked, P.K. told me he had been experiencing erectile dysfunction (ED) the last six months and that his quality of life was “terrible.”

Related: How a multi-component nutritional supplement benefits diabetic patients


Is fasting a viable option?

We talked about strategies for weight loss, including carbohydrate restriction, increased physical activity, and adding an injectable glucagon-like peptide 1 (GLP-1) agonist such as Victoza (liraglutide, Norvo Nordisk). We also discussed an oral sodium glucose transporter reuptake inhibitor (SGLT2-I) such as Jardiance (empagliflozin, Boehringer Ingelheim).

Both options have been shown to assist with weight loss in T2DM while also lowering CV risk.3,4

Lastly, I suggested he consider ADF per Dr. Fung’s protocol. He recommends an 1800 calorie low-carbohydrate Mediterranean-type diet which includes plentiful greens, avocadoes, walnuts and pistachios, fatty cold water fish (like salmon or tuna), a modest amount of bread or pasta on feeding days, and 12 cups of water or unsweetened tea only on fasting days.

I told P.K. that in order to prevent hypoglycemia, he would need to reduce his Lantus dose by 30 to 50 percent on feeding days and by 75 percent on fasting days. He would also have to rigorously check his blood glucose levels-adjusting his insulin dose and food intake depending upon his readings.

To my surprise (because about 20 other patients had flatly rejected this type of plan), P.K. agreed to try ADF for three months and see what happened.

Related: Keeping up with the latest diabetic eye disease research


Stick to the plan, see results

Four months later, P.K. returned to my office having lost nearly 40 lbs. (BMI=29.4).

His most recent A1C was 5.8 percent, and he had totally discontinued insulin therapy-remaining on 1000 mg metformin.

His PCP had also taken him off of metoprolol. P.K. reported that his ED had significantly improved, and stated that fasting has been the best thing he has ever done.

He asked me, “Why didn’t any of my other doctors suggest I try fasting?”


I recommended that he continue the diet most of the week, with lower caloric intake-900 calories-twice per week.

Related: The importance of multidisciplinary care for diabetes


Commitment key to success

I saw P.K. yesterday, and he has remained about 200 lbs. (BMI about 28) with an A1C under 6 percent on metformin monotherapy. He has no diabetes-related eye disease and a dramatically improved quality of life.

Fasting has been part of human existence for millennia from religious/spiritual practice and as a function of food scarcity.

Though fasting requires a high level of patient commitment, it could be a major help in both preventing and reversing T2DM as well as treating overweight/obese patients with diabetes and diabetes-related eye disease.

However, fasting could pose risk in some diabetes patients, including increased risk of:

Hyperglycemia with ketoacidosis resulting from inadequate insulin production (especially in type 1 diabetes) coupled with the hepatic breakdown of glycogen

Acute hypoglycemia for those using insulin or drugs that increase insulin production (e.g. glyburide [Diabeta, Sanofi])

Potential cardiovascular complications in those at high cardiovascular risk and/or with profound dehydration

Despite these concerns, many patients who are at low risk may benefit from consideration of this approach.5

RelatedWhat’s new for diabetes management and prevention


1. Dirks AJ, Leeuwenburgh C. Caloric restriction in humans: potential pitfalls and health concerns. Mech Ageing Dev. 2006 Jan;127(1):1-7.

2. Schübel R, Graf ME, Nattenmüller J, et al. The effects of intermittent calorie restriction on metabolic health: Rationale and study design of the HELENA Trial. Contemp Clin Trials. 2016 Nov:51:28-33.

3. Marso SP, Daniels GH, Brown-Frandsen K, LEADER Trial Investigators, et al. Liraglutide and Cardiovascular Outcomes in Type 2 Diabetes. N Engl J Med. 2016 Jul 28;375(4):311-22.

4. Zinman B, Wanner C, Lachin JM, EMPA-REG OUTCOME Investigators, et al. Empagliflozin, Cardiovascular Outcomes, and Mortality in Type 2 Diabetes. N Engl J Med. 2015 Nov 26; 373(22):2117-28.

5. Almalki MH, Alshahrani F. Options for Controlling Type 2 Diabetes during Ramadan. Front Endocrinol (Lausanne) . 2016 Apr 18;7:32. 

Read more from Dr. Chous here

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