The diet gets billed as a miraculously enjoyable diet—eat all the fat you want, just cut out the carbs. But the ketogenic diet (also called keto) was never supposed to be fun. It was supposed to treat severe epilepsy. And as a medical treatment, it was only intended to be administered under the supervision of trained nutritionists and physicians. The professionals would be able to monitor patients for potential problems and ensure that their diet was actually keeping them in ketosis—a metabolic state where your body switches from using glucose as energy to using ketone bodies, which come from body fat. They needed those checkpoints because staying in true ketosis is exceptionally challenging for adults.
The discovery of many appetite-related hormones provided molecular basis for appetite control, decreasing the relevance of the metabolites hypothesis (Karatsoreos et al., 2013). Recently, Sumithran et al. demonstrated that there is a long-term persistence of changes in some peripheral hormones involved in food control (Sumithran et al., 2011). In this study, they found a significant difference in mean levels of many food intake-related hormones 1 year after the cessation of weight loss via the hypocaloric diet. There was a long lasting decrease of anorexigenic compounds: leptin, PYY, cholecystokinin, insulin, and pancreatic peptide and an increase of the orexigenic molecule ghrelin. Moreover, they found that hunger remained elevated 1 year after diet cessation. In a successive study the same group investigated hunger-related hormones after 8 weeks of KD, demonstrating that during ketosis the increase of ghrelin (a strong stimulator of appetite) was suppressed (Sumithran et al., 2013). These results are consistent with those of Ratliff et al (Ratliff et al., 2009), who found no significant change in fasting plasma ghrelin after 12 weeks of VLCD.
The keto diet is one of the most effective that I’ve come across and one of the more straightforward (as opposed to easy!) to follow. In a nutshell, when you’re on a keto diet, you eat a very low-carb, high-fat diet. That means goodbye pasta and bread, hello cheese and oils. It’s pretty much the opposite of what we’ve been taught our entire lives. But it works if you follow the keto diet food list. Plus, you can make many favorite recipes keto-friendly.
Adipose tissue can be used to store fatty acids for regulating temperature and energy. These fatty acids can be released by adipokine signaling of high glucagon and epinephrine levels, which inversely corresponds to low insulin levels. High glucagon and low insulin correspond to times of fasting or to times when blood glucose levels are low. Fatty acids must be metabolized in mitochondria in order to produce energy, but free fatty acids cannot penetrate biological membranes due to their negative electrical charge. So coenzyme A is bound to the fatty acid to produce acyl-CoA, which is able to enter the mitochondria.
One downside to a ketogenic diet for weight loss is the difficulty maintaining it. “Studies show that weight loss results from being on a low-carb diet for more than 12 months tend to be the same as being on a normal, healthy diet,” says Mattinson. While you may be eating more satiating fats (like peanut butter, regular butter, or avocado), you’re also way more limited in what’s allowed on the diet, which can make everyday situations, like eating dinner with family or going out with friends, far more difficult. Because people often find it tough to sustain, it’s easy to rely on it as a short-term diet rather than a long-term lifestyle.