**1. Introduction**

Diet in diabetes has always been an area of much discussion. This is even more so now as there has been a lot of interest and research focusing on the relative contributions of carbohydrate and fat in diabetic diet affecting the overall metabolic profile. An area of confusion in diabetes diet is carbohydrates—Should one eat carbohydrates and to what extent or avoid

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© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

them? Another area that has traditionally always been important, although poorly understood, is the amount and type of fat that needs to be consumed; a lot of research is currently focussed on this matter.

The glycaemic index [6] categorises food dependant on the rate at which the body breaks it down to form glucose. High GI foods (white bread, potatoes and biscuits) are those that are quickly broken down into glucose. Low GI foods (whole grain bread, milk, leafy vegetables) are typically those that are broken down more slowly by the body. A low glycaemic index diet is beneficial for people with diabetes in keeping their glycaemic control more stable since they are less likely to cause rapid surges in blood glucose levels compared to high GI foods. Low GI food keeps one more satisfied and makes one feel less hungry before the next meal. Other advantages of lower GI foods include a higher nutritional value, a varied diet and reduced

Low-Carbohydrate High-Fat (LCHF) Diet: Evidence of Its Benefits

http://dx.doi.org/10.5772/intechopen.73138

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A carbohydrate controlled diet is a diet in which carbohydrate intake is either limited or set at a particular value, to help stabilise blood glucose levels in patients with diabetes. Examples of such diets are low-carbohydrate diets, Atkins diet, ketogenic diets, low-carb high-fat diet

This is a diet where intake of carbohydrate is pre-set, thereby offering less flexibility in terms of meals through the day. It is simple to follow and offer consistency and is especially useful for those on fixed-dose insulin regimens. People with type 1 diabetes do need to have compe-

Low-carbohydrate diets are a form of restricted carbohydrate diet. Restricted carbohydrate diets set a limit on how much carbohydrate can be consumed over the course of a day or for each meal. This can help reduce hunger and prevent wide swings in blood glucose levels

If carbohydrate and calorie intake is kept low enough, this form of dieting can not only help maintain good glucose control but also help promote regular ketosis and aid weight loss. It is

Many people with diabetes, both type 1 and type 2, are following a low-carb diet because of its benefits in improving diabetes control, weight loss, flexibility and simplicity. Carbohydrates, like proteins and fats, provide energy to help fuel the body. Carbohydrate is the nutrient which has the greatest effect on blood sugar levels and requires insulin to be produced by the

important to maintain a healthy balance of nutrients including fruit and vegetables.

immediate demand for insulin following eating.

**3. Carbohydrate controlled diets**

(LCHF), South beach diet and the Zone diet.

**3.1. Fixed carbohydrate diet**

tence in carbohydrate counting.

**3.2. Restricted carbohydrate diets**

responsible for causing hunger.

**3.3. Low-carbohydrate diet**

It is currently unclear as to the exact percentage of calories that is required from carbohydrate, protein and fat in the diet for the diabetes patient—this should be based on metabolic needs and targets for the preferred individual. There are a variety of popular diets (low carb, intermittent fasting, low fat, ketogenic, mediterranean, vegetarian, DASH, very low calorie, Adkins, 5:2 and commercial food points) for patients to choose from in order to make informed decisions about their diet.

Over the years, many researches have focused on the relative importance of the right proportion of carbohydrates and fat combination in a balanced diabetic diet with some recent research challenging traditional viewpoint of the importance of one over the other. Jury is still out regarding the relative merits and demerits of a diabetic diet—low-carbohydrate high-fat or low-fat high-carbohydrate diet.

Low-carbohydrate high-fat (LCHF) diets are an upcoming although a debatable topic in current nutrition. Since the publication of Dr. Atkins' Diet Revolution in 1972 [1], LCHF diets have divided the opinion of medical fraternity significantly. Some believe that these diets effectively treat type 2 diabetes mellitus (T2DM), obesity and metabolic syndrome [2, 3], while others consider them too non-conventional and in conflict with current globally accepted dietary guidelines that advocate low-fat high-carbohydrate (LFHC) diets to reduce the risk of cardiovascular disease [4, 5]. Given such conflicting opinions, the medical profession may be unsure how to advise on the right diet for the individual patient with diabetes.

This chapter focuses on the basic physiology and metabolism of carbohydrate and fat in patients with diabetes and reviews the literature on these two diet combinations with current thoughts and evidence on this core issue affecting insulin utilisation in the individual with diabetes.

The aim of this chapter is to provide current thinking and evidence behind LCHF diets and in the process and to provide clinicians with additional evidence to inform their clinical decision-making and understanding the potential benefits of these eating plans for at least some patients.
