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Effect of Ketosis on Appetite Hormones



sharma-obesity-protein-shakeOne of the most remarkable clinical observations in people embarking on severely calorie-restricted ketogenic diets, is the almost complete lack of hunger that occurs within a few days of dieting.

Although clinically well described, the biological basis for this “appetite suppressant” effect of ketosis is less well understood.

Now, Priya Sumithran and colleagues from Melbourne University, Australia, in a paper published in the European Journal of Clinical Nutrition, describe the hormonal alterations associated with weight loss induced by a ketogenic diet.

Their study included 39 non-diabetic overweight or obese subjects who completed an 8-week ketogenic very-low-energy diet (VLED), followed by 2 weeks of reintroduction of foods.

During the ketogenic VLED, subjects lost 13% of initial weight and fasting ketones (β-hydroxybutyrate) increased significantly as expected.

This increase in ketones was accompanied with a suppression of the increase in ghrelin normally seen with weight loss. weight-reduced subjects also had significantly lower leptin, peptide YY, amylin and pancreatic polypeptide levels, compared with week 10 values. In contrast, Fasting GIP, glucagon-like peptide 1 and CCK were not different in weight-reduced subjects between weeks 8 and 10. In addition subjective ratings of appetite were lower at week 8 than after refeeding.

The authors describe their significant findings regarding the effect of ketosis on ghrelin as follows:

“In mildly ketotic participants, the increase in the circulating concentration of ghrelin, a potent stimulator of appetite, which otherwise occurs as a result of diet-induced weight loss, was suppressed. The present findings are in keeping with a recent report of a 12-week carbohydrate-restricted diet, during which 28 overweight subjects lost ~6.5% of their starting weight without a significant change in fasting plasma ghrelin. In our study, postprandial ghrelin concentrations were also measured, and found to remain unchanged following weight loss as long as subjects were ketotic. After refeeding, fasting and postprandial ghrelin concentrations rose significantly.”

No doubt, these findings provide a plausible biological basis for the clinical observation of suppressed hunger and appetite in individuals on ketogenic diets and may well explain the better long-term adherence to such diets in clinical practice.

The observed increase in ghrelin on “refeeding” is also in line with the often observed immediate onset of “cravings” and discontinuation of the diet the minute patients come off their strictly ketogenic regimen. Thus, for example, patients paradoxically often find the highly caloric restrictive phase of total liquid formula diets (e.g. Optifast) far easier to comply with that the loosening of this regimen with the introduction of “real” food.

In conclusion, this study clearly demonstrates that circulating concentrations of several hormones and nutrients which influence appetite are significantly altered after weight loss induced by a ketogenic diet, compared with after refeeding.

Clearly, a better understanding of these mechanisms could one day lead to interventions that may help improve the long-term adherence to dietary caloric restriction.

AMS
Edmonton, AB

ResearchBlogging.orgSumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A, & Proietto J (2013). Ketosis and appetite-mediating nutrients and hormones after weight loss. European journal of clinical nutrition PMID: 23632752

3 Comments

  1. From DebraSy:

    just wanted to send a little note thanking you for yesterday’s post.

    Today’s also relates, in that the study confirms that management of hormones is critical to weight-loss maintenance, regardless of methodology of the loss. Back when I was blogging I tried to explain how these hormones feel on the inside – the distracting and perpetual “eat impulses” they cause – and I got a lot of affirmation from my fellow maintainers and others who had tried to maintain but couldn’t because of the hormones, which create a different kind of sensation than pure insulin-triggered hunger and are often marginalized by the cultural mythology of “emotional eating.” Boy, is that a misused and overused phrase! While my fellow weight-loss maintainers and other blog followers got my message clearly, doctors (present company excepted) just don’t get it.

    I cannot express how discouraging it is that my internist and ob/gyn, both of whom I’ve been seeing since 1996, think I’m “cured” (and have held this opinion since the weight loss). They think I’m in need of no particular assistance or even understanding. When I tell them I am not cured, they say something like, “Well, of course it’s challenging, but certainly it’s worth the rewards!” Then they immediately move on to what they think is “important,” since my weight simply is not an issue anymore. I’m sure they have written in my file that I am some kind of hypochondriac or problem patient, since I always bring an article, study, link to your blog, or something related to maintenance, which they accept with a gracious condescension that makes me seethe, since it’s obvious at the each annual visit they didn’t even look at my last “gift.”

    I so appreciate that you keep the blog going daily. It’s gotta be chipping away at the ignorance, if not with my particular doctors, then with others. I see my ob/gyn in two weeks. I will bring her another “gift.” Who knows, maybe this time she’ll read it. Maybe this time she’ll click onto your blog.

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  2. The ignorance you speak of Debra is entrenched and systemic. I’ve had a bariatric surgeon refuse to do gastric sleeve on me despite a lifetime of yo-yo weight fluctuation because guess what, I’m not fat enough! BMI is 32 so I’m to be punished for not having ‘co-morbidities’, get back to us when you get fatter. Great attitude. The overall attitude of ‘experts’ and doctors alike is to just eat less and move more. If I hear be more person try to counsel me about ’emotional eating’ I will surely scream. After losing 20kg on my own I’m stuck in no mans land now having to do the research for myself because ‘experts’ don’t bother looking deeper. No amount of wishful thinking mindful eating or counselling is going to restore my leptin levels or fix the myriad other hormonal and biochemical imbalances that drive my eating behaviour and lethargy. What they don’t get is that a formerly fat person NEVER really ends up with the same ‘normal’ body fat regulation system of a non-dieted person who’s never been fat EVEN AFTER they’ve lsy a lot of weight.

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  3. Would you Do a Radio show on the wellwesswithkim radio show on ketosis

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