5 Nutrition
Questions
The Atkins’ diet is a low-carbohydrate diet used to promote weight loss. The principle is that the body will switch from burning glucose to burning fat. Atkins did (in addition to the diet) recommend exercise and nutritional supplements. However, like all diets, although there might be short-term gains, permanent weight loss is rare and patients should be encouraged to maintain the recommended healthy intake of food (Table 5.1). In the long-term, the diet may increase the development of atherosclerosis.
| Dietary component | Approximate amounts (% of total energy unless otherwise stated)* | General hints |
|---|---|---|
| Total carbohydrate | 55 (55–75) | Increase fruit, vegetables, beans, pasta, bread |
| Free sugar | 10 (<10) | Decrease sugary drinks |
| Protein | 15 (10–15) | Decrease red meat (see fat below) |
| Total fat | 30 (15–30) | Increase vegetable (including olive oil) and fish oil and decrease animal fat |
| Saturated fat | 10 (<10) | |
| Unsaturated fat | 20 | |
| Cholesterol | <300 (<300) mg/day | Decrease meat and eggs |
| Salt | <6 (<5) g/day | Decrease prepared meats and do not add extra salt to food |
| Total dietary fibre | 30 (>25) g/day | Increase fruit and vegetables and wholegrain foods |
* Values in parentheses are goals for the intake of populations, as given by the World Health Organization (including populations who are already on low-fat diets). Some of the extreme ranges are not realistic short-term goals for developed countries, e.g. 75% of total energy from carbohydrate and 15% fat. (From Kumar and Clark Clinical Medicine 7e.)
These are effective long-term treatments but have complications and side-effects.
There is no single lifestyle factor. There appear to be number of causes, including taking less exercise, watching television and playing computer games, as well as an increase in food intake, particularly of fatty, sugary foods that are very rich in calories. The different degrees of overweight are shown in Table 5.2.
Table 5.2 Ranges of body mass index (BMI) used to classify degrees of overweight and associated risk of comorbidities
| WHO classification | BMI (kg/m2) | Risk of comorbidities |
|---|---|---|
| Overweight | 25–30 | Mildly increased |
| Obese | >30 | |
| Class I | 30–35 | Moderate |
| Class II | 35–40 | Severe |
| Class III | >40 | Very severe |
Cholesterol is synthesized in the body, mainly in the liver. The higher the amount of cholesterol in the diet, the lower the amount of cholesterol synthesized, and vice versa. Thus, it is difficult to significantly lower your serum cholesterol by diet alone unless the diet is very restrictive. Familial hypercholesterolaemia is related to a reduction in the number of low-density lipoprotein (LDL) receptors.
