The FastDay Forum

Just remembered a conversation at a dinner party a week ago with someone to whom I was explaining my 5:2 method and how successful it has been.

first words

you cant fast /go on 5:2 (or other fasting method i guess) if you are a diabetic.

thoughts?

Much depends on the type of diabetes (1, 1:5, 2 or 3) and the person's history.

I know people who've used ADF in the form of the JUDDD (Johnson Up Day, Down Day) and they've reversed diabetes II to the point where their physicians have removed them from all medication (including insulin/Byetta, not just oral interventions such as Metformin).

That said, Dr Johnson strongly warns against people with any variety of diabetes adopting an ADF schedule because of the risk that the VLC days might lead to brittle liver dumps of over-reactive hyperglycaemia and worsen blood sugar control.

The people for whom it worked (and who've posted about their experiences) lost substantial amounts of weight. Since achieving maintenance, the ones that I know of not only maintain with something like a 5:2 schedule but also observe an eating window in a day with a restricted number of meals in order to limit the frequency of insulin release. All but one of these was diagnosed with Type II.

The ones who did it, had some early successes and promising results and then stopped posting - I've no idea what happened to them. 3 of these were Type 1 or 1.5.

I can think of several people who were categorised as pre-diabetic by HbA1C who followed IF in some form or another and along with shedding weight, they moved back down from the pre-diabetic state to a more 'normal' HbA1C.

But, there are hard to validate reports of people whose blood sugar and general blood work deteriorate with IF, even if they're having success with weight loss. It's difficult to know what's happening there and if there is a relevant contraindication from (say) a genetic test or family history.

[carorees]

I have written about some of the scientific studies on IF done with people with diabetes in the fasting pages linked to in the yellow menu bar:

Fasting>Health benefits>How can intermittent fasting help diabetes?

and

Fasting>Fasting with medical conditions>Fasting with type 2 diabetes

Welcome back Caro@carorees Hope you had a good hol x

The critical point to keep in mind here is that you should NOT jump into doing an intermittant fast if you are diabetic AND are taking any of the following pills that lower blood sugar: gliclazide, glibenclamide, glipizide. (These are the sulfonylurea pills.) If you are taking repaglinide with meals. it may be possible to fast if you skip the repaglinide on fast days.

It may also be impossible to fast if you are using any of the basal insulins like Lantus, Levemir, or NPH unless you understand how to adjust your dose on your own. Even then, because of the way these insulins work, it may not be possible to get them to work with intermittent fasting schedules.

That is because all these drugs are dosed with the assumption that you are eating carbs throughout the day. If you aren't, they continue to lower your blood sugar which can give you nasty hypos.


If you are using Byetta (exenatide) or Victoza, Januvia, Onglyza, Trajenta, or combo pills with these drugs in them it probably isn't dangerous to fast as they don't lower blood sugar when you aren't eating the way the first batch of pills I listed do.

If you aren't taking the drugs that lower blood sugar in the absence of food, you CAN fast even with a diabetes diagnosis. Though you should test your sugar during the fasting part of the day because some people with diabetes will see their blood sugar shoot up as they fast. In that case, eat a small breakfast, then fast.

It is perfectly safe to fast while taking metformin, in fact, metformin makes fasting extremely easy as it tends to eliminate the hunger that drives so much overeating.

It is so annoying the way that doctors will make these blanket statements because they don't have the patience to explain the actual facts to people. For that matter, it's annoying that doctors don't explain to patients what exactly it is that the drugs they prescribe do to lower their blood sugar. That's a whole nother topic. But if people understood the mechanisms of these drugs and their actual, proven side effects, they would be much more aggressive in demanding only the safer drugs on offer.

Interesting - my husband is Type 1 and I can't imagine that he would be able to fast - am sure it would cause havoc with his sugar levels but I haven't read the research so feel free to correct me!

GREAT Q/A here, thanks! As a T2 insulin user, I approached my doctor after reading as much as I could about IF & diabetes. My experience (only, different for all), has been reduction in daily glucose, blood pressure, LDL & cholesterol. I have also had reductions in liver enzymes which had previously been elevated. My doctor is supportive, which also helps. I have reduced both types of insulin - with Dr. supervision. I have also found 16:8 on non-fast days helpful. So, like we keep observing , we have to experiment with what works for individual folks. One last comment, on the rare occasion I have had a hypoglycemic episode, I treat it & don't worry about the fast day calories. One does have to be mindful after all

@MLCDz,

Your doctor is a jewel. You are so lucky to have one who will work with you that way!

Where I live, it is impossible to find an endocrinologist who will even support people with diabetes who want to cut their carbs down sharply. I can only imagine how they would respond to the idea of. Most of these doctors are so busy that they pass all but their most critical patients to Nurse Practitioners who tend to be very rigid and order them to eat x grams of carbs each day, use a dose of y units, and that is the end of the discussion. It's good to know there are doctors out there who are more open to experimenting with new approaches!

And you are absolutely right. If you use pure glucose to treat hypos and use just enough that you don't create a rebound high blood sugar, the calories are negligible and get burnt off immediately.

My sister has been diagnosed with T2, though I'm fairly sure she has been misdiagnosed and really has T1.5. They are basing her T2 diagnosis on the fact that one family member (paternal grandmother) had T2. She controlled it without insulin and drugs, just by losing weight and eating right. My sister, however, is tiny, became insulin dependent fairly soon after her diagnosis, and also has hypothyroidism (not sure that it's the autoimmune type, but still… all 3 of these things are signs of T1.5). Since it's basically like T1, I'm not sure IF would be any good for her. She gets hypoglycemic, or close to it, a lot.

In this situation, I would normally say consult your doctor, but I'm not sure all of them have the brains and/or current info/understanding necessary to give good advice! (Evidently T1.5 is very under-diagnosed)

I think fasting (but also just losing weight and eating healthier) really helps insulin resistance, but it's not going to bring beta cells (insulin producing cells of the pancreas that get attacked by the immune system in T1 and T1.5) back. I.e., my guess is that IF is good for T2, but not T1 or T1.5.

There is often crossover between other autoimmune conditions and a T1.5 type diabetes. This is something I know quite a lot about. Hashimoto's Thyroiditis is autoimmune. Low thyroid also leads to increased insulin resistance, making it harder to control with dropping insulin levels.

And yes, doctors are mostly clueless about most of the various forms of T1.5. Some go beyond clueless to dangerously toxic. I have heard from several people with T1.5 who were told they had T2 because they were overweight and ended up in the ER with ketoacidosis before they could get a diagnosis.

Has your sister had testing for islet and GAD antibodies? A C-peptide test? In the U.S. Type 1 style results on those tests will qualify a person for insurance coverage of a pump (assuming they have insurance) which is often the best approach for getting back into control.

But I would NOT suggest fasting to anyone dealing with a full fledged T1 style insulin regimen unless they are very experienced in adjusting their own doses. Even then, the key with control with T1 is so often keeping things on a very even keel, so the fluctuations introduced by fasting could be very problematic.