Ketosis
An online intervention comparing a very low-carbohydrate ketogenic diet and lifestyle recommendations versus a plate method diet in overweight individuals with type 2 diabetes: a randomized controlled trial.
Saslow LR et al (2017). Journal of Medical Internet Research, 19(2):e36
The authors’ previous trial, an in-person intervention, found that recommendations to follow a very low-carbohydrate ketogenic diet (ad libitum) and to change lifestyle factors (physical activity, sleep, positive affect, mindfulness) helped overweight people with type 2 diabetes/prediabetes improve glycaemic control and lose weight. This pilot feasibility study found that an online intervention based on their previous recommendations resulted in better glycaemic control and greater weight loss for people with type 2 diabetes than those randomised to an online programme based on a conventional, low-fat diabetes (‘plate method’) diet. The authors suggest that online delivery of ketogenic diet and lifestyle strategies may afford them a wider reach in the successful self-management of type 2 diabetes.
Rethinking fat as a fuel for endurance exercise.
Volek JS, Noakes T, Phinney SD (2015). European Journal of Sport Science, 15(1):13-20.
A key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability, coupled with an inability to effectively utilise alternative lipid-fuel sources. Current fuelling tactics that emphasise high-carbohydrate intakes before and during exercise inhibit fat utilisation. The most efficient approach for accelerating fat oxidisation is to reduce dietary carbohydrate intake enough to induce nutritional ketosis, while increasing fat intake; after a period of 3-4 weeks with total daily carbohydrates at such a low level, the human body adapts to be able to use almost all fat as its fuel. The coordinated metabolic adaptations that ensure proper inter-organ fuel supply during such low-carbohydrate availability are referred to as keto-adaptation. Beyond providing a stable fuel source for the brain, the major circulating ketone body, beta-hydroxybutyrate, acts as a signalling molecule capable of altering gene expression and eliciting complementary effects of keto-adaptation that could extend physical/mental performance beyond current expectation. The authors propose that the shift to fatty acids and ketones as primary fuels during dietary carbohydrate restriction could be of benefit for some athletes.
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Middle and long-term impact of a very low-carbohydrate ketogenic diet on cardiometabolic factors: a multi-center, cross-sectional, clinical study
Cicero AFG et al (2015). High Blood Pressure and Cardiovascular Prevention, 22(4):389-394.
A short-term ketogenic diet managed in the setting of general practice seemed able to improve a large number of anthropometric, haemodynamic and metabolic parameters related to cardiovascular disease risk, with improvements maintained in the long-term. The authors note that ‘this is the first report one can find in the literature of the efficacy and tolerability of a short-term ketogenic intervention on overweight and obese patients outside highly specialised centres, with a relatively long follow-up after intervention end’.
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Do ketones really suppress appetite? A systematic review and meta-analysis.
Gibson A et al (2015). Obesity Reviews, 16:64-76.
Very-low-energy diets (VLEDs) and ketogenic low-carbohydrate diets (KLCDs) are two dietary strategies that have been associated with a suppression of appetite. This systematic literature search and meta-analysis provides the first quantitative evidence that appetite is significantly reduced (less hunger, greater fullness/satiety) during weight loss in response to a ketogenic intervention.
Ketogenic diet for obesity: friend or foe?
Paoli A (2014). International Journal of Environmental Research and Public Health, 11:2092-2107.
Many studies have shown that ketogenic diets have a solid physiological and biochemical basis and can induce effective weight loss along with improvement in several cardiovascular risk parameters. Moreover, there is some evidence that ketogenic diets may have positive effects on mood in overweight subjects. Even if during the very early phase of a ketogenic diet (the first 4 or 5 days) subjects may sometimes complain of lethargy, this effect passes rapidly and subjects subsequently report an improved mood. A period of low carbohydrate ketogenic diet may help to control hunger and may improve fat oxidative metabolism and therefore reduce body weight. Correctly understood, the ketogenic diet can be useful to treat obesity.
Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets
Paoli A, Rubini A, Volek JS, Grimaldi KA (2013). European Journal of Clinical Nutrition, 67:789-796.
Very-low-carbohydrate diets or ketogenic diets have been in use since the 1920s as a therapy for epilepsy and can, in some cases, completely remove the need for medication. From the 1960s onwards they have become widely known as one of the most common methods for obesity treatment. Recent work over the last decade or so has provided evidence of the therapeutic potential of ketogenic diets in many pathological conditions, such as diabetes, polycystic ovary syndrome, acne, neurological diseases, cancer and the amelioration of respiratory and cardiovascular disease risk factors. The possibility that modifying food intake can reduce or eliminate pharmaceutical methods of treatment, which are often lifelong with significant side effects, calls for serious investigation. This review revisits the meaning of physiological ketosis in the light of this evidence and considers possible mechanisms for the therapeutic actions of the ketogenic diet on different diseases. It also questions whether there are still some preconceived ideas about ketogenic diets, which may be presenting unnecessary barriers to their use as therapeutic tools in the physician’s hand.
Ketosis and appetite-mediating nutrients and hormones after weight loss.
Sumithran P et al (2013). European Journal of Clinical Nutrition, 67:759-764.
During a ketogenic VLCD, subjects lost 13% of their initial weight and their fasting levels of ketone bodies increased significantly. Furthermore, when they were ketotic, the expected weight loss-induced increase in the ‘hunger’ hormone ghrelin was suppressed. These results indicate that levels of several appetite-influencing hormones and nutrients were altered after weight loss induced by a ketogenic diet VLCD, and that these changes actively combat the usual increase in appetite seen during weight reduction.
Ketosis, ketoacidosis and very-low-calorie diets: putting the record straight
Mullins G, Hallam CL, Broom I (2011). Nutrition Bulletin, 36:397-402.
‘Very-low-calorie diets (VLCDs) are used to treat obesity, often in a non-clinical setting, and the typical formulation of a minimum of 50 g carbohydrates daily can induce a mild dietary ketosis. This clinically benign state is sometimes confused with the non-metabolically adapted state of ketoacidosis, and this misunderstanding may lead to the rejection of VLCDs as a suitable obesity treatment. This paper summarises and discusses the difference between physiological ketosis and pathological ketoacidosis, the benefits of ketosis-inducing weight-loss regimen such as VLCDs and why ketoacidosis should never be the diagnosis in a non-type 1 diabetic on a carbohydrate-restricted diet.’
The neuroprotective properties of calorie restriction, the ketogenic diet, and ketone bodies.
Maalouf MA, Rho JM and Mattson MP (2009). Brain Research Reviews, March, 59(2):293-315.
‘The therapeutic potential of calorie restriction and the ketogenic diet have been repeatedly demonstrated in clinical settings and in various animal models of neurological disease. The underlying mechanisms involve an improvement in mitochondrial function, a decrease in the expression of apoptotic factors and an increase in the activity of neurotrophic factors…The present review describes the neuroprotective effects of calorie restriction, the ketogenic diet and ketone bodies and compare the molecular mechanisms of action of these interventions.’
Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum.
Johnstone AM et al (2008). American Journal of Clinical Nutrition, January, 87(1): 44-55.
‘In the short term, high-protein, low-carbohydrate ketogenic diets reduce hunger and lower food intake significantly more than do high-protein, medium-carbohydrate non-ketogenic diets.’
