Being overweight is a particular problem in patients with one of the acute porphyrias because reducing the intakes of carbohydrate and energy in an effort to lose weight can worsen these diseases. Severe acute attacks have occurred in patients who attempted to lose weight rapidly with very low energy diets. Patients with acute Porphyria should avoid very low energy diets, and should inform their physician or nutritionist that they have one of these diseases before they enter a weight-loss program. Also, they should not participate in a weight loss program except under the supervision of a physician.
Patients with acute Porphyria who are overweight and wish to lose weight should be prescribed a diet that will result in gradual weight loss. The energy intake should be 500 to 1000 kilocalories (or not more than 10 percent) below that needed to maintain weight. The diet should be well balanced and nutritionally complete. It may require time and considerable discipline to adjust one's diet to a moderately reduced level of energy intake. The patient will need to learn more about foods and the nutritional contents of foods in order to be successful in losing weight with this type of regimen. In contrast, entering a "crash diet" program requires little knowledge of nutrition in order to achieve a short term loss of weight.
It may seem that overweight patients with Porphyria are at a distinct disadvantage, because it is unsafe for them to enter into programs that can lead to rapid loss of weight. It should be remembered, however, that most overweight individuals who lose weight rapidly eventually regain the lost weight. A regimen of moderate energy restriction, such as that recommended here, is in fact the medically preferred method of weight loss for all individuals. A patient who achieves the discipline and knowledge about diet that is required to lose weight in this manner is likely to enjoy more favorable long term results. In addition to avoiding attacks of Porphyria, other medical complications of very low energy diets (gallstones, for example) do not occur with a regimen of moderate energy restriction.