**3. Carbohydrate controlled diets**

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

#### **3.1. Fixed carbohydrate diet**

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

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

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

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

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

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

Carbohydrates have a direct influence on blood sugar levels—diabetes diet therefore tends to focus either on carbohydrate portion size or the speed at which carbohydrates are absorbed by the body. Patients with diabetes are generally advised to follow a low GI diet rather than

focussed on this matter.

72 Diabetes Food Plan

informed decisions about their diet.

or low-fat high-carbohydrate diet.

**2. Glycaemic index (GI) and diabetes**

with diabetes.

diabetes.

patients.

a low-carb 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 competence in carbohydrate counting.

#### **3.2. Restricted carbohydrate diets**

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 responsible for causing hunger.

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

#### **3.3. Low-carbohydrate diet**

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 body. Lowering sugar levels reduces need for insulin and this can also help reduce insulin resistance and improve metabolic profile.

**4. The controversy about high fat intake**

fat stores for energy.

metabolic syndrome [10].

diet would appear to be groundless.

profession.

[46, 47].

Consuming fats have very little direct effect on blood glucose levels, and as a result does not lead to an increase in insulin levels. The principle of LCHF diet is to replace carbohydrate intake with fat, thus reducing insulin levels and increase the body's ability to utilise its own

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

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

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Metabolic syndrome is a conglomeration of three or more risk factors (elevated waist circumference, elevated triglycerides, low HDL-c, high blood pressure and elevated glucose). Metabolic syndrome is a condition of insulin resistance and can lead to obesity, type 2 diabetes, fatty liver and many other conditions [9]. A LCHF dietary approach can be used to reduce insulin levels and therefore can also be an effective method for treating or preventing the

With LCHF diets, there is an increased intake from fats and proteins, and concerns have been raised about the potential dangers of their increased intake. As has been shown a number of times in the past [11–15], a reduction in dietary carbohydrate intake does not necessarily cause a concomitant increase in total fat and protein intake. The absolute amounts of energy intake often remain very similar, as total energy intake decreases on LCHF diets (although proportional amounts of energy supplied from fat and protein increase). Nevertheless, it is this absolute or relative increase in fat intake that causes a lot of anxiety within the medical

Current dietary guidelines do not define a specific limit in terms of fat intake [16, 17]. Moreover, a few articles in the lay and scientific literature suggest that the intake of total fat (mainly, saturated fats) may not need to be limited [2, 18, 19]. American Diabetes Association position statement for type 2 diabetes recommends that a total fat intake of 20–35% may be desirable for reducing the risk of obesity and suggests minimising carbohydrate intake, but it

The diet heart hypothesis based largely on Ancel Keys' original Seven Countries Study [20] suggested that saturated fat intake is the direct cause of coronary atherosclerosis. This theory is now being questioned as it is not supported by current evidence [21–31], which finds no association between saturated fat intake and all-cause mortality or progression of coronary atherosclerosis [32]. Instead, higher fat intakes have been associated with lower rates of ischaemic stroke in men [33] as evidenced by a continued decline in coronary mortality in the Japanese with high blood cholesterol levels [34] and high fat intake [35]. To the contrary, it has been shown that LCHF diets sometimes show significant improvements in coronary risk factors [36–39] and the fear of adverse effects from the increased (saturated) fat intake on this

Benefits of replacing saturated fats with dietary polyunsaturated fats may not be as strong [40–44] and even harmful [44, 45]. Again, there is no evidence to suggest that the intake of moderate amounts of red meat has detrimental effects on conventional coronary risk factors

has refrained from specifying ideal amounts of macronutrients [16].

Insulin is also being the fat storage (anabolic) hormone in the body; thus, reducing insulin in the body with a low-carb diet can help with losing weight. People also generally reduce their calorie intake. This together with the satiating influence of fat helps with further weight loss. However, people on medications, such as insulin, sulphonylurea or glinides, should be careful about hypoglycaemia.

Low-carbohydrate diets have been said to provide diabetes patients with more energy levels through the day. There is less craving for sugary and snack foods. As a result of lower glucose results and improved HbA1c, there is clearer thinking process and less 'brain fog'. People have also found that low-carb diets can improve cholesterol and triglyceride levels.

There are various ways of following a low-carbohydrate diet—one will need to cut down on common foods like bread, pasta, rice, potatoes and sweet processed foods. There are a number of other ways to replace starchy foods—such as using swede or celeriac instead of potato and using cauliflower instead of rice. A healthy low-carb diet should also have a strong vegetable intake and moderate protein (unprocessed meat) and fat intake from natural sources (to provide a balance of monounsaturated, polyunsaturated and saturated fat).

In 2015, Diabetes UK launched the Low Carb Program [7], which has helped thousands of people with type 2 diabetes to improve their diabetes control and reduce their dependency on diabetes medication.

The counterargument against low-carb diets for people with diabetes is that there is not enough evidence to support the effectiveness and safety of low-carbohydrate diets in the medium to long term. However, more and more research and evidence seems to be favouring low-carb diets in general.

Diabetes UK has put together a position statement [8] to explain how low-carb diets might be used to help manage diabetes using the best level of evidence from systematic reviews, metaanalyses and randomised controlled trials.

Diabetes UK suggests that low-carb diets can be safe and effective for people with type 2 diabetes. They can help with weight loss and glucose management and reduce the risk of cardiovascular disease. So, they recommend a low-carb diet for some people with type 2 diabetes. But there is no consistent evidence that a low-carb diet is any more effective than other approaches in the long term, so it shouldn't be seen as the diet for everyone. Currently, there is no strong evidence to say that a low-carb diet is safe or effective for people with type 1 diabetes. Because of this, Diabetes UK does not recommend low-carb diets to people with type 1 diabetes.

Evidence for low-carb diets in children reports adverse effects such as poor growth, a greater risk of cardiovascular disease and psychological problems. So, low-carb diets are not recommended for children with diabetes.
