Aims: Better understanding of the influence of body mass to plantar peak pressure as a main biomechanical risk factor for ulcerations in the diabetic foot. To predict the effect of weight change on peak pressure. Methods: In-shoe peak pressure measurement (PEDAR, Novel) are performed in 5 patients with diabetic neuropathy and 5 controls: all wearing the same kind of ready made shoes with ready made standard fitting insoles of cork. Each subject is measured in 3 modes of weight simulation: normal weight, 20 kg weight increase (waistcoat with weight pieces) and 20 kg weight release by a movable overhead suspension covering a 6m walkway. Pace is selected individually after some pre-test walking to be comfortable in all 3 weight modes. For data analysis the plantar area of the foot is divided into 6 regions, particularly metatarsal region and heel. Results: No significant difference between diabetics and controls is found. In the most threatened regions (metatarsals and heel) peak pressure increases and decreases linearly with weight: A simulated weight change ± 20 kg increases/ decreases metatarsal peak pressure by ± 6.4 N/cm2. The corresponding figure for the heel region is ± 2.6 N/cm2. Conclusions: Weight increase or weight loss in the individual patient has at least in the metatarsal and heel region a significant effect to the plantar peak pressure. The linear relationship allows for a simple method of predicting the effect of weight change to peak pressure