The modern western diet is not well tolerated by most aging adults. Our eating habits if unchecked often lead to the development of metabolic syndrome and insulin resistance. Insulin resistance leads to higher blood sugar and overall more glucose flux throughout the day. This typically along with lack of activity, decreased sleep, and increased stress lead to the development of cardiovascular disease and other chronic diseases as we age. The foundation for staying healthy is to decrease inflammation and reduce the occurrence of metabolic syndrome and insulin resistance. This can be done through lifestyle changes and diet. We must keep in mind that fad diets often lead to a “yo-yo” effect which has its own negative effects on our health. The diet one chooses ought to be a shift in the overall way one eats to something that can become a new routine way of eating throughout his life.
A ketogenic diet (KD) is one of the diet choices that clearly shows positive effects on our health. KD has been shown to reverse insulin resistance, restore normal metabolic function, improve overall cholesterol profiles, and have a generally positive effect on cardiovascular health.
So what is a KD? KD is one in which somebody restricts their total daily carbohydrate load to <50g and in most cases <20g to induce ketosis. Protein is eaten in moderate amounts and fat is purposely consumed as your highest percentage of calories. Saturated fat is often the preferred fat choice in these instances.
For most people, the body is using glucose as its primary energy source. Meaning it is metabolizing carbohydrates into sugar which the body then uses as energy. One must keep a constant supply of carbohydrates for this to continue. When carbs are restricted glucose reserves (glycogen stored in liver and skeletal muscle) are used up and become insufficient to provide energy to the body. This normally takes place in approx. 2 days. This results in the liver beginning to produce ketones, which are used as an alternative energy source throughout the body and brain.1
Ketones are produced from fat and on a KD our body shifts its fuel supply to run almost entirely on fat. Insulin level are reduced, and blood sugar remains much more consistent which leads to correction of metabolic syndrome and dramatically increases fat burning. This process is sped up and helped along by intermittent fasting (IF). IF can be carried out in a few different ways but ultimately leads to a reduction in the number of hours you spend eating foods. Often IF is carried out by fasting for 14-16 hours each day and eating for 8-10 hours each day. IF will be discussed in a different article.
In rodent studies, a KD diet clearly equates to a reduction in fat2. Experience and research show that this carries over into humans. KD improve glucose tolerance and increase insulin sensitivity.3,4,5 Insulin sensitivity and the development of type 2 diabetes (T2D) is an important predictor for the development of metabolic syndrome, cardiovascular disease, and other chronic disease processes as we age. Improved glucose tolerance and insulin sensitivity can have a very positive effect on body mass and overall health as we grow older. Studies have shown that a carb restricted diet can lead to a reduction in medications in T2D6. The research also shows that T2D had a significant improvement in fasting blood glucose at 12 weeks and 56 weeks when fed a KD7.
In regards to cholesterol, the following may seem counterintuitive after what you have likely been told about fat and saturated fat consumption but a KD has been associated with significant reductions in total cholesterol8, a reduction in triglycerides levels9,10, reductions in LDL cholesterol levels9, and an increase in HDL cholesterol9,10,11. For those who are not up on the terms let me just point out that those are great things. You are getting a reduction of bad cholesterol and an increase of good cholesterol. This equates to improved cardiovascular function and overall heart health.
Studies on KD and blood pressure are difficult to find but one did show an improvement in both systolic and diastolic BP in obese participants during 48 weeks compared to a low-fat diet12.
The following is a direct quote from ‘Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies’ by Christophe Kosinski1 and François R. Jornayvaz13
“Three meta-analyses about the effect of KD on cardiovascular risk factors were published recently14,15,16. Their conclusions are unanimous about general positive effects, but not unanimous about every single variable. Santos et al. concluded in 2012 that low-carbohydrate diets lead to a significant decrease in body weight, BMI, abdominal circumference, both systolic and diastolic blood pressure, triglycerides levels, fasting plasma glucose and HbA1c, an increase in HDL cholesterol levels, and no change in LDL cholesterol levels.”
This write up is short and to the point. Soon I will produce a longer article that is more in-depth on the actual foods one should eat and the day to day carrying out of the KD. The purpose here was simply to show the overall benefits of a KD. I still need to produce information on a KD benefits in reversing metabolic syndrome and reducing inflammation which I will do at a later date.
Owen O.E., Morgan A.P., Kemp H.G., Sullivan J.M., Herrera M.G., Cahill G.F. Brain metabolism during fasting. J. Clin. Invest. 1967;46:1589–1595. doi: 10.1172/JCI105650.
Kennedy A.R., Pissios P., Otu H., Roberson R., Xue B., Asakura K., Furukawa N., Marino F.E., Liu F.F., Kahn B.B., et al. A high-fat, ketogenic diet induces a unique metabolic state in mice. Am. J. Physiol. Endocrinol. Metab. 2007;292:E1724–E1739. doi: 10.1152/ajpendo.00717.2006.
Badman M.K., Kennedy A.R., Adams A.C., Pissios P., Maratos-Flier E. A very low carbohydrate ketogenic diet improves glucose tolerance in ob/ob mice independently of weight loss. Am. J. Physiol. Endocrinol. Metab. 2009;297:E1197–E1204. doi: 10.1152/ajpendo.00357.2009
Samaha F.F., Iqbal N., Seshadri P., Chicano K.L., Daily D.A., McGrory J., Williams T., Williams M., Gracely E.J., Stem L. A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity. N. Engl. J. Med. 2003;348:2074–2081. doi: 10.1056/NEJMoa022637. [PubMed] [Cross Ref]
Foster G.D., Wyatt H.R., Hill J.O., McGuckin B.G., Brill C., Mohammed B.S., Szapary P.O., Rader D.J., Edman J.S., Klein S. A Randomized Trial of a Low-Carbohydrate Diet for Obesity. N. Engl. J. Med. 2003;348:2082–2090. doi: 10.1056/NEJMoa022207. [PubMed]
Yancy W.S., Foy M., Chalecki A.M., Vernon M.C., Westman E.C. A low-carbohydrate, ketogenic diet to treat type 2 diabetes. Nutr. Metab. 2005;2:34. doi: 10.1186/1743-7075-2-34.
Dashti H.M., Al-Zaid N.S., Mathew T.C., Al-Mousawi M., Talib H., Asfar S.K., Behbahani A.I. Long term effects of ketogenic diet in obese subjects with high cholesterol level. Mol. Cell. Biochem. 2006;286:1–9. doi: 10.1007/s11010-005-9001-x.
Dashti H.M., Al-Zaid N.S., Mathew T.C., Al-Mousawi M., Talib H., Asfar S.K., Behbahani A.I. Long term effects of ketogenic diet in obese subjects with high cholesterol level. Mol. Cell. Biochem. 2006;286:1–9. doi: 10.1007/s11010-005-9001-x
Long term effects of ketogenic diet in obese subjects with high cholesterol level.
Dashti HM, Al-Zaid NS, Mathew TC, Al-Mousawi M, Talib H, Asfar SK, Behbahani AI
Mol Cell Biochem. 2006 Jun; 286(1-2):1-9
Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo. Brinkworth GD, Noakes M, Buckley D, Keogh JB, Clifton PM Am J Clin Nutr. 2009 Jul; 90(1):23-32
A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. Sharman MJ, Kraemer WJ, Love DM, Avery NG, Gómez AL, Scheett TP, Volek JS J Nutr. 2002 Jul; 132(7):1879-85.
Two diets with different haemoglobin A1c and antiglycaemic medication effects despite similar weight loss in type 2 diabetes. Mayer SB, Jeffreys AS, Olsen MK, McDuffie JR, Feinglos MN, Yancy WS Jr Diabetes Obes Metab. 2014 Jan; 16(1):90-3
Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies Christophe Kosinski1 and François R. Jornayvaz
Santos F.L., Esteves S.S., da Costa Pereira A., Yancy W.S., Jr., Nunes J.P. Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors: Low carbohydrate diets and cardiovascular risk factors. Obes. Rev. 2012;13:1048–1066. doi: 10.1111/j.1467-789X.2012.01021.x.
. Bueno N.B., de Melo I.S., de Oliveira S.L., da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: A meta-analysis of randomised controlled trials. Br. J. Nutr. 2013;110:1178–1187. doi: 10.1017/S0007114513000548