Weight loss is a major concern in most developed countries. With surveys showing that the majority of adults in the US are trying to lose or maintain weight (Freedman, King and Kennedy. 2012). Current fads and diets are constantly changing and it’s becoming more difficult for people to get a handle on what is right and wrong. With most people not using the standard recommended guidelines to lose weight (Freedman, King and Kennedy. 2012) it’s clear that there needs to be greater emphasis on the different practices that do and do not work. Successful long-term weight loss is defined by the institute of medicine as a 5% reduction that lasts at least a year (Freedman, King and Kennedy. 2012). In a survey done on Americans it was found that over 70% of them used each of the following weight loss methods at least once in a 4 year period; increased exercise, decreased fat intake, reduced food amount and reduced calories (Freedman, King and Kennedy. 2012).
The concept of a low-carbohydrate high-fat (LCHF) diet has been around since 1862 when William Banting published his letter stating he cured William Harvey’s obesity by avoiding starchy foods (Noakes. 2013). There has been an increased level of interest in recent years with influential researchers such as South African professor Tim Noakes and his interest in its effect on endurance sports as well as the health benefits. There are varying levels of intake that can be described as ‘low’ or ‘high’ which will be discussed during part two.
The basis for the low-carbohydrate aspect of this diet is that a high-carbohydrate diet can lead to harmful diseases such as type 2 diabetes mellitus. This is a disease that is characterised by high blood sugar (Mbombi et al 2012) caused by an inability of the muscles to allow the glucose molecules in. Normally insulin would be released from the pancreas which would then bind with the muscle to set off a chain of reactions that brings the glucose transporter (GLUT 4) to the cell membrane, allowing the glucose to pass through (Roper. 2006). This is a progressive disease which may start with the pancreas simply producing more insulin to allow the glucose to enter the muscles but can end in total insulin deficiency. It is essential that something is done before it reaches this stage. The LCHF diet may be an answer to this in that there is significantly less carbohydrate (sugars) being ingested and so the pancreas does not have to work as hard to produce insulin. This seems simple enough yet it is a highly debated subject amongst nutritionists.
Essentially a LCHF diet is based on the fact that to lose fat it must be burnt, so by increasing the body’s fat metabolism it’s possible to decrease the amount of fat stored. So along with the low-carbohydrate the other factor in the LCHF diet is the high-fat intake; this is again a hotly contested subject. Traditionally fat has always been viewed as the ‘bad guy’ in this scenario, with carbohydrate accounting for as much as 70 % of daily calorie intake. The high-fat component as discussed above is about increasing the body’s ability to burn fat, not just to lose weight, but also to be used as the primary fuel source.
Effects on sporting performance
It has been a long standing ‘fact’ that to perform at a high level in sport you must be on a high-carbohydrate diet and supplement with carbohydrate during endurance exercise. Noakes, Volek and Phinney (2014) suggest that there is no reason why our abundant fat stores could not provide enough energy to fuel the body during sub maximal exercise. The problem that does arise is the ability to burn fat at a high enough level to supply the body with sufficient energy. While this is something can be trained there is a great deal of work involved, including periods of adaptation where performance may be significantly reduced.
If this short introduction to the background of a LCHF diet interested you then please check back for part two where we will be looking at the current research surrounding the use of the LCHF diet and whether it is or is not an effective diet.