Transitioning off keto diets is not as simple as one would think. The perception many have is that they’ll lose weight with keto, get to their goal, and switch back.
Unfortunately, this isn’t really how it works. Many people have misconceptions about carbs, type 2 diabetes, and obesity.
The primary myth is that a high carbohydrate diet causes poor blood glucose regulation that progresses to Type 2 diabetes. I used to believe this. The data simply doesn’t support this idea.
The simplistic view is that people eat too many carbs and over time this wears out their pancreas. Since the pancreas secretes insulin, which helps lower blood glucose, this drives chronic hyperglycemia.
You simply need to look at the data to know this is incorrect. Type 2 diabetics secrete more insulin, and over time they end up losing the beta cells in the pancreas that produce it. But moving from healthy to pre-diabetic to the early stages of type 2 isn’t about carbs.
The Twin Cycle Theory
Therefore, type 2 diabetes and jacked up blood glucose regulation are more a symptom of the problem. In other words, there are underlying pathological changes that occur in insulin signaling due to excess fat. This drives an inability to control blood glucose levels. Lose the fat, fix the problem.
But that doesn’t mean a healthy person who eats carbs is wearing out their pancreas. If that were happening, you’d see progressive decreases in insulin production as you transition from healthy to pre-diabetes to overt type 2 diabetes. But that’s just not what happens.
Interestingly, research has identified the gut as a central player in blood glucose regulation.
How the gut regulates blood glucose
The gut is an active player in blood glucose regulation. This makes sense since this is where we absorb a large amount of glucose from our diet. The gut regulates glucose via secretion of incretin hormones.
Glucagon-like peptide 1(GLP-1) is an incretin hormone secreted by the intestine to help regulate blood glucose levels. Enteroendocrine cells in the intestine secrete GLP-1 which increases glucose stimulated insulin release. It also delays gastric emptying so glucose doesn’t elevate too high.
GLP-1 has no major effect on fasting glucose. Instead, it makes the pancreas more sensitive to circulating glucose so that it can be more responsive as blood glucose levels rise. Additionally, it increases beta cells in the pancreas.
As a result of this infotmation, pharmaceutical drugs that stimulate GLP-1 production are common treatments for type 2 diabetes. And if you’re looking at transitioning off keto, new evidence indicates that this mechanism is critically important.
Not that you have to transition off keto, you can stay on it if you like. But if you like carbs like me, completely eliminating them forever is no bueno.
Transitioning off keto: How GLP-1 may play a role
When someone has gastric bypass, there are fairly rapid changes in the way they regulate blood glucose. Again, if they had “worn out” their pancreas, this wouldn’t happen.
But what does happen? A recent paper looked at the role GLP-1 plays in this process. Interestingly, it indicates GLP-1 may play an important role int the rapid improvements seen in Roux-en-Y gastric bypass surgery.
During Roux-en-Y gastric bypass surgery, doctors effectively “unhook” the stomach and duodenum from the GI tract. A very small gastric pouch is left and connected directly to the jejunum.
This makes the stomach smaller and bypasses the duodenum where most absorption occurs. Clearly, doing this makes people eat and absorb less energy. Interestingly, it also increases GLP-1 secretion.
G:P-1 secretion and the jejunum
As it turns out, the jejunum is an important part of the gut for GLP-1 secretion. As free fatty acids enter the jejunum, enterocytes absorb and use them for energy. The last step of this process is the generation of ketones: intestinal ketogenesis.
In this paper, they found that intestinal ketogenesis inhibited GLP-1 in mice. In humans undergoing Roux-en-Y bypass surgery, expression of the rate limiting gene for ketone production, mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHMGCS), decreased ~3.8-fold. Finally, in vitro, ketone bodies inhibited GLP-1 production by 40%
Ultimately, free fatty acids are not available when they hit the jejunum because they’re still triglycerides. As a result, the jejunum doesn’t absorb as many fatty acids. Consequently, intestinal ketogenesis is inhibited and GLP-1 production increases.
This data implies that intestinal ketogenesis plays a role in regulating GLP-1 secretion from the gut. Therefore, GLP-1 may be a major player in the impaired glucose tolerance seen in people doing a ketogenic diet.
What does this tell us about transitioning off keto?
So, this is a cool mechanisms and all, but what does it tell us about transitioning off keto? It actually tells us a few things. First, this effect is dependent on a large amount of fatty acids entering the jejunum. Therefore, if you’re in the process of losing weight, it’s probably moot.
But if you’re at maintenance or eating too much, you’ll probably have a difficult time tolerating carbohydrates. Step 1 is to decrease fat intake.
Well, that’s not entirely true. Step 1 should be to practice good circadian hygiene. GLP-1 is a circadian hormone, so you should optimize your light environment, feeding/fasting cycle, and activity patterns.
Once you’ve done that and increased your fat intake, there are other steps you can take to make the transition smoother:
- Stick to slower digesting carbs-Carbs stimulate GLP-1, but they most is secreted in the jejenum. Processed carbs, being already digested, are absorbed well before then.
- Consume more fiber-Butyrate formed in the colon from fiber fermentation causes GLP-1 secretion.
- Swap out saturated fats for monounsaturated fats and polyunsaturated fats-This is a big problem for many caught up in the low carb community who are also following the PUFA drama. Human data shows that certain UFAs are better than SFAs for GLP-1 secretion.
It’s also important to reintroduce carbohydrates slowly and gradually over time.
Conclusion
Ultimately, with proper planning and a logical approach, transitioning off keto or a low carb diet isn’t all that difficult. I did this several years back and currently consume upwards of 300g of carbohydrate a day with an excellent hemoglobin A1c of 4.9& and a rock-solid lipoprotein insulin resistance(LPIR) score of 20.
Lock down your circadian rhythms, stick to slower digesting carbs, consume more fiber, and swap out some saturated fats for unsaturated fats. Over time you’ll have no problem at all consuming carbs provided you’re under your personal fat threshold.
You don’t have to feel trapped if you want to transition of a keto diet and eat carbs again. It simply takes a bit of knowledge, time, and patience.
Use the information in this blog to help transition and you’ll be eating carbs in no time!
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