Keto Diets for Blood Sugar
Does a high-fat diet lower blood sugar?
The low-carbohydrate, high-fat ketogenic (keto) diet that promotes the production of ketone bodies has been gaining more attention over the last few years. It has also gained interest among diabetics as it was shown to reduce blood sugar levels, body weight, triglycerides and improve cholesterol metabolism [1,2,3]. But is this diet really recommended for managing blood sugar and diabetes?
In fact, studies have shown that individuals can achieve lower body weight, lower blood sugar levels, as well as lower triglycerides and better cholesterol metabolism just by lowering the amount of carbs in their diet, without adding high-fat ingredients [4,5,6]. In addition, a low-carb, high-fat diet was shown to be more effective in reducing blood sugar levels compared to high-carb, low-fat diets, meaning that lowering carbohydrates has a greater impact on improving metabolic health than lowering fats [1,7]. These studies suggest that simply eating less carbs, without increasing fats, may be sufficient to lower blood sugar levels and body weight for people who are concerned.
In addition, improving the quality of carbs in the diet, rather than lowering the quantity, may be more important. Eating more fibers and whole-grain foods might reduce the risk of developing type 2 diabetes and insulin resistance [8,9]. Switching from processed carbs (white carbs, breakfast cereals, sweet snacks & drinks) to brown carbs can dramatically help in managing blood sugar levels, and also prevent the levels from getting too low (hypoglycemia).
Adding more fat to the diet, for example cooking with more butter or eating more fried food, may actually have negative effects on blood sugar control and diabetes complications [10,11,12]. Excess fat is toxic in the body (lipotoxicity) and contributes to insulin resistance and pancreatic damage [13,14,15,16]. Also, foods with higher protein and fat, and processed meats - particularly those that are heated when cooking - have significantly higher content of AGEs (Advanced Glycation End-products) [17,18,19]. High levels AGEs in the blood contribute to insulin resistance [20,21] and diabetes complications [22,23,24].
Diabetics should also note that too much ketones can cause a condition called diabetic ketoacidosis, where high ketone levels turn the blood too acidic.
The relationship between fat and sugar is complex. Eating too much fatty food can actually worsen the damage caused by high blood sugar. So the keto diet, which encourages the body to produce more ketones, is not generally recommended for people concerned about blood sugar levels [25].
Summary
Eating more fat to encourage ketone bodies is not recommended
Simply choosing whole-wheat or high-fiber carbs may be enough to lower blood sugar levels and body weight
Sources:
https://dx.doi.org/10.3945/ajcn.115.112581
https://dx.doi.org/10.1016/j.nut.2012.01.016
https://dx.doi.org/10.7326/0003-4819-140-10-200405180-00006
https://dx.doi.org/10.1016/s0002-9343(02)01129-4
https://dx.doi.org/10.1089/154041903322716714
https://dx.doi.org/10.1059/0003-4819-153-3-201008030-00005
https://dx.doi.org/10.1001/archinte.166.3.285
https://dx.doi.org/10.2337/diacare.27.2.538
https://dx.doi.org/10.1371/journal.pmed.0040261
https://dx.doi.org/10.1001/jama.290.7.912
https://dx.doi.org/10.1152/ajpendo.00361.2010
https://dx.doi.org/10.1042/BJ20021617
https://dx.doi.org/10.1007/s00125-010-1684-1
https://dx.doi.org/10.1016/j.plipres.2005.11.002
https://dx.doi.org/10.3810/pgm.2001.04.908
https://dx.doi.org/10.1007/s001250051130
https://dx.doi.org/10.1016/j.jada.2004.05.214
https://dx.doi.org/10.1016/j.jada.2010.03.018
https://dx.doi.org/10.1371/journal.pone.0118652
https://dx.doi.org/10.2174/138161208784139747
https://dx.doi.org/10.1007/s11892-013-0453-1
https://dx.doi.org/10.3109/07853899608999102
https://dx.doi.org/10.4330/wjc.v4.i4.90
https://dx.doi.org/10.1002/biof.1018
https://dx.doi.org/10.3390/nu11050962