Early American explorers who had to survive solely on lean meats, such as rabbits, sometime developed medical problems that resembled starvation. This condition, known as protein poisoning or rabbit starvation, is a medical condition in which your body does not get enough of the required nutrients even though you're eating sufficient amounts of calories. Protein poisoning is rare, though it is possible if you only eat lean meats.
Macro and Micro-Nutrients
There are two main categories of nutrients: macro and micro. Macro-nutrients are those nutrients that provide calories to your body: fats, proteins and carbohydrates. Micro-nutrients are those nutrients that do not supply calories but which our bodies require to function properly, such as water, vitamins and minerals. You need to regularly eat both micronutrients and macronutrients in order to maintain optimal health. Failing to do so can result in malnutrition, starvation and nutrient deficiencies.
Your body uses energy taken from macronutrients to carry out bodily functions. When you eat food, it contains a certain amount of energy measured as calories. According to the University of Illinois at Urbana-Champaign, a single gram of protein provides 4 calories. The average person needs about 2,000 calories per day, though this amount differs depending on your age, sex and activity level. It is possible to get all the calories your body needs by eating protein, but at the expense of limiting the other macronutrients. Obtaining a high percentage of your calories from protein is what leads, over time, to protein poisoning.
Protein is a key macronutrient and one your body needs to survive. Proteins are composed of amino acids. After ingesting protein, your body breaks down those amino acids and uses them to replace the proteins that exist in your body. The United States Department of Agriculture recommends that you get about 10 to 35 percent of calories from protein, while you need about 20 to 35 percent of your calories from fat and the remainder from carbohydrates.
Eating a diet too high in protein can, after several weeks, result in death. According to the Food and Nutrition Board of the National Institute of Medicine, "rabbit starvation" can occur when you get 45 percent of your calories from protein. Such protein-rich diets can lead to symptoms that include nausea, weakness and diarrhea, those these symptoms abate when the protein content of your diet is reduced by increasing the amount of fats or carbohydrates.