Obesity causes a significant deterioration of lymphatic function in all lymphoedema and lipohyperplasia dolorosa patients. Seventy-six percent of all lymphoedema patients are not normal weight. Between 50 and 88% of all LiDo patients are overweight. The obesity epidemic has effects on lymphoedema and lipohyperplasia dolorosa. In lymphatic diseases, obesity, as an additional morbidity, leads to the aggravation of the primary disease. The obesity pandemic can be countered only with individual and long-term dietary changes: reduce hyperinsulinemia, fight inflammation, improve lymph flow. Hypoproteinaemia can itself lead to oedema, so that an optimal protein supply is essential for lymphoedema patients and LiDo patients, while a protein-deficient diet worsens the symptoms. The metabolic and pro-inflammatory consequences of obesity are of decisive pathophysiological importance. Through fat modification instead of fat avoidance, a high proportion of anti-inflammatory omega-3 fatty acids from plant and marine sources and a minimal share of pro-inflammatory omega-6 fatty acids should be achieved. The aim is a ratio of 1:3–1:5. In contrast to protein requirements, the amount of carbohydrates, in addition to genetic factors, is largely dependent on physical activity. Dietary interventions as therapeutic measures in people with lymphatic diseases must aim primarily at reducing hyperinsulinaemia and breaching insulin resistance as well as combating chronic inflammation caused by obesity.