No, insulin probably isn’t the cause of constant hunger, according to Dr. Stephan Guyenet. Dr. G gives 11 points of evidence in support of his conclusion. Read them for yourself. Here are a few:
- multiple brain-based mechanisms (including non-insulin hormones and neurotransmitters) probably have more influence on hunger than do the pure effect of insulin
- weight loss reduces insulin levels, yet it gets harder to lose excess weight the more you lose
- at least one clinical study (in 1996) in young healthy people found that foods with higher insulin responses were linked to greater satiety, not greater hunger
- billions of people around the world eat high-carb diets yet remain thin
An oft-cited explanation for the success of low-carbohydrate diets involves insulin, specifically the lower insulin levels and reduced insulin resistance seen in low-carb dieters. They often report less trouble with hunger than other dieters.
Here’s the theory. When we eat carbohydrates, the pancreas releases insulin into the bloodstream to keep blood sugar levels from rising too high as we digest the carbohydrates. Insulin drives the bloodstream sugar (glucose) into cells to be used as energy or stored as fat or glycogen. High doses of refined sugars and starches over-stimulate the production of insulin, so blood sugar falls too much, over-shootinging the mark, leading to hypoglycemia, an undeniably strong appetite stimulant. So you go back for more carbohydrate to relieve the hunger induced by low blood sugar. That leads to overeating and weight gain.
Read Dr. Guyenet’s post for reasons why he thinks this explanation of constant or recurring bothersome hunger is wrong or too simplistic. I agree with him.
The insulin-hypoglycemia-hunger theory may indeed be at play in a few folks. Twenty years ago, it was popular to call this “reactive hypoglycemia.” For unclear reasons, I don’t see it that often now. It was always hard to document that hypoglycemia unless it appeared on a glucose tolerance test.
Regardless of the underlying explanation, low-carb diets undoubtedly are very effective in many folks. And low-carbing is what I always recommend to my patients with carbohydrate intolerance: diabetics and prediabetics.
So, “it’s complicated”? No surprise there—
“The insulin-hypoglycemia-hunger theory may indeed be at play in a few folks. Twenty years ago, it was popular to call this “reactive hypoglycemia.” For unclear reasons, I don’t see it that often now. It was always hard to document that hypoglycemia unless it appeared on a glucose tolerance test.”
I think there are a few reasons for this.
1. What used to be known as “reactive hypoglycemia” then tends to be called “insulin resistance” now.
2. Home meters weren’t readily available to non-diabetics 20 years ago. They were expensive, bulky, time consuming, needed larger blood samples and difficult to calibrate.
3. Reactive Hypoglycemia is an INSULIN issue. It may or may not show during an oral GTT because that measures GLUCOSE and often the issues with blood glucose aren’t apparent until the latter stages of pre-diabetes. Doctors who checked INSULIN levels did see the problem. Are you familiar with the work of Joseph Kraft, for example??? http://m.meridianvalleylab.com/?url=http%3A%2F%2Fmeridianvalleylab.com%2FKraft-prediabetes-profile-patterns-overview&utm_referrer=#2932
4. Reactive hypoglycemia is not the same as hypoglycemia. When I was eating too many carbs all the time, it was a rapid decrease in blood glucose that caused symptoms (shakiness, anxiety, agitation, etc). When my blood sugar started out at 190, a drop to 150 certainly would not have been diagnosed as hypoglycemia. But my body certainly thought so. It’s a false hypo, but the symptoms feel just as awful.
5. Now, keeping my carbs low, my average BG is in the mid 80’s and I rarely feel bad unless my BG is in the 50’s.
6. C-Peptide which measures insulin production levels for me (insulin resistant PCOS) went from very high to normal levels with LCHF. PCOS symptoms improved dramatically.
I get that other hormones are involved, too, but of course it’s the insulin.
Yes. I wholeheartedly agree with #4. If we are very high to begin with and then drop very quickly, we feel low but aren’t actually anywhere near a true low…just much LOWER and it feels like falling off a cliff. Then once we get back to “normal” we feel better. Even if normal is sky-high. Since switching to LCHF I rarely feel low or shaky or excessively hungry at all.
Thanks for you input, Amy.
Jan, I appreciate your input.
I heard about Dr. Kraft about a year ago, IIRC. I need to know more about him. One of the bloggers I follow promotes his work. I wonder if his studies have been replicated by other investigators.
I’ve run into a few patients with T2 diabetes who have consistently run serum glucoses in the 200-300 mg/dl range (14 mmol/l), then when they hit the normal range (e.g., 100 mg/dl or 5-6 mmol/l), they feel bad and have hypoglycemia-like symptoms that respond to carbohydrate ingestion. Doctors don’t understand that very well. They eventually tolerate the lower levels, but it’s a slower, gradual process over months.
“I heard about Dr. Kraft about a year ago, IIRC. I need to know more about him. One of the bloggers I follow promotes his work. I wonder if his studies have been replicated by other investigators.” I doubt very much if it’s been replicated simply because these are expensive tests to run. I believe he had EVERY patient in his general practice do a 5 hour GTT with insulin levels. I can’t even get my HMO to cover a single fasting insulin level. His sample size was pretty large, and somewhat randomized in that he had everyone in his practice tested, not just the ones with symptoms of hyperinsulemia.
Here’s a link to the pharmacist blogger I mentioned who informed me of Dr. Kraft’s work: