The processing of both plant and animal raw materials by the food industry generates a large amount of waste. Waste products are rarely used in the production chain, and, at best, serve as animal feed products. Unprocessed waste products cause additional disposal costs and also constitute a burden on the natural environment. Concern for the natural environment and the desire to optimize the use of raw materials as well as semifinished products encourage producers and scientists to look for opportunities to reuse what was previously considered worthless waste products. Food industry waste can provide a range of bioactive substances that can improve the nutritional value and functionality of new products. They often contain significant amounts of protein, dietary fiber, fat, vitamins, and a whole range of other biologically active substances. Examples of such waste products that increase the nutritional value of new products are fruit and vegetable pomace, spent coffee grounds, and post-fermentation residues. These products can be used to enrich food products, extend shelf life, or obtain fiber preparations. This strategy fits perfectly into the current trend of zero-waste technology and sustainable development. The possibilities of using the entire range of waste products to obtain products with high added value depend on the ingenuity and creativity of both scientists and food producers, and are not limited to those included in this elaboration.