In the research presented in the paper, the harvest losses for the winter wheat crop, carried out over three years (2012, 2013 and 2014), based on the agro-ecological principles of the food chain evaluation, were assessed from the point of view of food security, using the quantitative and energetic indicators. Harvest losses were investigated at primary production levels: E0 (technological works); E1 (harvesting); E2 (transportation); E3 (storage), the quantitative production values and detailed energy consumption per unit of area and unit of agricultural product being studied. The results indicate that harvest losses are a vulnerability to food security and can undermine the general state of security environment, increase the technological costs per unit of processed agricultural surface. Harvest losses considerably load the costs for each calorie of food processed from primary agricultural raw material. The study of the amount of harvest losses has identified the critical point of energy conversion efficiency in the wheat crop agroecosystem, on the basis of which we can provide criteria for improving the principles of production across all food chain directions, including the processing, storage and distribution stages of finished foods.