In an excellent review by Noakes and Wind in the British Journal of sport, the two authors evaluate the value of a LCHF diet and without fear or favour pointed out the benefits and pitfalls of such a diet. What follow is a summary of this article. The original article appears in Br. J Sports Medicine 2017; 51: 133-139
Numerous studies indicate that a very low carbohydrate diet (below 50 grams carbohydrates per day) is exceptional beneficial for Diabetes Type 2 patients as well as obese patients.
Since the carbohydrate content of the diet is significantly reduced, the relative proportion of energy derived from protein or fat will increase. In practice however the LCHF diet typical produce a reduction in hunger. The result is that a person on LCHF diet usually experience a decrease in caloric consumption, sometimes significantly.
Very LCHF (ketogenic) diets may induce ketosis in some people. Though individual responses vary, ketosis usually occurs in people who restrict their carbohydrate intake to below 20–50 g/day with exercise and protein restriction.
What is a LCHF diet: food with a focus on eating unprocessed food, consisting primarily of leafy vegetables, nuts , eggs, fish, unprocessed animal meats, dairy products and plant fats e.g. avocados, coconuts and olives.
Several studies show that LCHF diets are more effective that other diets in weight loss. Some studies emphasize the relative ease of adopting a LCHF diet and losing weight.
How does LCHF diet brings about weight loss?
Increased protein of LCHF cause a lower energy intake without hunger
1) Increase protein intake supress satiety.
2) Ketogenic LCHF diets cause low grade nausea in most people that suppresses appetite.
(3) Carbohydrates in food causes insulin to spike and that causes hunger. This does not happen in LCHF diets.
LCHF diets have a further advantage that could not be explained by less calories intake. Most people never felt that they eat that amount of less food for the big weight loss they experienced.
We do know that LCHF diets increase reliance on fat oxidation for energy production, especially during exercise,as shown by increased blood ketone concentrations. This lead to lipolysis with breakdown of a patients fat stores.
LCHF diets and Type 2 Diabetes Mellitus (T2DM)
T2DM is primarily a condition of IR, with persistent hyperglycaemia as a result of excessive hepatic glucose production.Of all the macronutrients, carbohydrates cause the greatest and most prolonged increases in blood glucose and insulin concentrations. It is therefore no surprise that prior to the discovery of insulin, carbohydrate restriction, often associated with fasting or even starvation, was the eating plan prescribed for all diabetic patients regardless of type (1 or 2). Today, LCHF diets are again a potential first-line treatment for T2DM.
Numerous studies of which most are quoted in this website prove that a LCHF diet decreases HbA1c levels more than any other diet. HbA1C is an indication of a person’s blood glucose value over the last 3 months. Numerous examples exist where people could lower or stop their antidiabetic drugs after introducing a LCHF diet.
LCHF diets and cardiovascular risk factors
Evidence from numerous randomized control studies indicate that LCHF diets consistently produce more favourable changes in many measures of cardiovascular risk than do LFHC diets. This applies especially in persons with insulin resistance, type 2 Diabetes, atherosclerotic dyslipaedemia and Non Alcoholic fatty liver disease.
Examination of blood lipid concentrations in RCTs reveals that LCHF diets have a potent effect in lowering blood TG concentrations, to a significantly greater degree than do LFHC diets. Blood ApoB concentrations—an indirect measure of lipoprotein particle numbers and also a risk predictor for coronary artery disease—also decrease more on LCHF than on the LFHC diet.
Furthermore, of all dietary interventions, none increase HDL-C concentrations as effectively as do LCHF diets.
NAFLD, AD and LCHF
NAFDL= Non Alcoholic Fatty Liver disease
Cardiovascular disease is the leading cause of death in NAFLD,a condition causing elevated TG and low HDL-C concentrations with overproduction of very-low density lipoproteins and impaired clearance of TG-rich lipoproteins. Hepatic IR is also increased in persons with fatty liveras shown by inadequate suppression of hepatic glucose production by insulin in NAFLD
Since NAFLD is caused by excessive carbohydrate,the finding that a carbohydrate-restricted LCHF diet can reverse AD is more readily explained. The LCHF diet reverses the NAFLD and hence the AD that it causes.