Excessive intake of fat has been linked to a variety of diet-related chronic diseases, such as diabetes, obesity, cardiovascular disease, and cerebrovascular disease. At the same time, fat provides calories and nutrients to the human body, as well as impacting the appearance, taste, texture, and palatability of foods. Consequently, it is not feasible to simply remove fats from food, without adversely affecting their nutritional, functional, and sensory properties. Emulsion gels are colloidal viscoelastic materials that can be used to mimic the appearance, taste, texture, and other properties of fats, while still providing valuable fat-soluble nutrients, like vitamins and nutraceuticals. In this article, we review the design and preparation of emulsion gels based on different food-grade biopolymers, including proteins, polysaccharides, and their complexes. In addition, we discuss how structural design principles can be used to create emulsion gels that exhibit a diverse range of different properties. The potential applications of emulsion gels as fat replacers in different kinds of foods are briefly summarized. When properly designed, emulsion gels can convert healthy plant-based liquid oils into semi-solid plastic fats that can mimic many of the rheological characteristics of animal fats. In conclusion, emulsion gels provide an effective approach for designing healthier and more nutritious low-fat foods.