**9. LCHF diets and cardiovascular risk factors**

Greater satiety on LCHF diets in persons responding to the diet may result from a number of mechanisms, including increased protein intake, which promotes satiety [65]; ketogenesis,

Although still controversial, it has been suggested that LCHF diets may provide a metabolic 'advantage' favouring greater weight loss, despite the ingestion of an equal number of calories. This metabolic advantage could be related to thermogenic effects of protein intake, greater protein turnover for gluconeogenesis and loss of energy through excretion of ketones in sweat or urine [67, 68]. This state of increased lipolysis with reduced lipogenesis contributes to a metabolic milieu theoretically favouring fat loss. This effect is dependent on reduced blood insulin concentrations, uniquely produced

Any diet that reduces carbohydrate load and insulin concentrations will have a beneficial effect on diabetes. Therefore, LCHF diets are currently being discussed as a potential first-line

Three hundred and sixty-three patients, who were overweight and obese, were given either a ketogenic LCHF diet or a 'low calorie, high nutritional value' diet in a 6-month trial [71]. Those with T2DM (102 patients) had significantly lower HbA1c and fasting glucose levels and

Thirty-four prediabetic or T2DM patients were randomised to a calorie-restricted diet according to American Diabetes Association (ADA) guidelines or a very LCHF diet in another 3-month trial [72]. HbA1c did not alter in the ADA group, whereas in the very LCHF group, there was a significant reduction (6.6–6.0%) in HbA1c, decrease in the use of anti-diabetic

Westman et al. [73], in their 24-week trial comparing a very LCHF diet with a low GI diet, similarly showed greater decreases in HbA1c (−1.5% vs. −0.5%, p = 0.03) with the very LCHF

In another study, 115 obese adults with T2DM were randomised to either LCHF or LFHC diet for 1 year [74]. Both diets showed significant weight loss and HbA1c reduction. LCHF diet, however, resulted in better blood glucose stability, greater reductions in diabetes medication

Although it could be assumed that all the above positive metabolic changes with an LCHF diet is attributable to its associated weight loss, it is also well established that carbohydrate restriction in diabetes patients per se improves glycaemic control even in the absence of

diet, despite more patients reducing or stopping their diabetes medications.

requirements and significant improvements in all aspects of lipid concentrations.

which suppresses appetite [66] and fewer instances of rebound hypoglycaemia.

by the LCHF diet.

78 Diabetes Food Plan

treatment for T2DM [69, 70].

weight loss [75, 76].

**8. LCHF diets in the management of T2DM**

also lost more weight (−12.0% vs. −7.0%) with the LCHF diet.

medications and weight loss (−5.5 vs. −2.6 kg).

An understandable concern with any increased dietary fat intake on the LCHF diet is the increased risk of future cardiovascular disease. This is largely based on the Ancel Keys' original seven countries study [20], which led to the development of traditional LFHC dietary guidance. However, there is good evidence emerging now that LCHF diets significantly alter cardiovascular risk more so than LFHC diets, especially in those with T2DM and metabolic syndrome.

Many RCTs show that LCHF diets lower blood triglyceride [77] and blood apoprotein B concentrations significantly more than do LFHC diets [3, 78–81]. Furthermore, no other diet increases HDL-C concentrations as effectively as do LCHF diets, which outperform LFHC [79, 82, 83] low glycaemic index [84] and many other diets.

Tay et al. [79] compared a very LCHF with an LFHC diet over a 1-year period—despite similar weight loss, there was significantly more lowering of blood TG concentrations (−0.58 vs. −0.22 mmol/L) and greater increase in HDL-C concentrations (+0.30 vs. +0.07 mmol/L) with the LCHF diet. This has huge connotations for reducing coronary artery disease and would be especially beneficial for those with insulin resistance.

A contentious issue regarding the LCHF diet is the variable LDL-C response to the increase in dietary fat intake. Some trials show a decrease or non-significant change in LDL-C concentrations [38, 85], whereas others report a more marked increase in LDL-C levels [86]. Tay et al. [79], in their study, have demonstrated that both LDL-C (+0.6 vs. +0.1 mmol/L) and total cholesterol (+0.7 vs. +0.1 mmol/L) concentrations increased significantly more in those following the LCHF diet.

Many other systematic reviews [87] and trials [88] have confirmed similar positive effects on overall lipid profile. However, one needs to remember that LDL-C concentrations predicted by the Friedewald equation becoming increasingly inaccurate at low blood TG concentrations [89] as seen with the LCHF diet. It has been shown that LCHF diets consistently reduce the proportion of small, dense LDL particles while increasing the number of large, buoyant LDL particles [3, 81, 85, 90–92].

Additionally, LCHF diets have been associated with improvements in flow-mediated arteriolar dilation [80], decreased inflammatory biomarkers [14], lower systolic and diastolic blood pressures [3], improved glycaemic control with reduced HbA1c, plasma glucose and insulin concentrations [87] and preferential reduction in visceral and liver fat—changes in these surrogate markers would be expected to reduce cardiovascular risk significantly [3, 93].
