Ketones are the breakdown products of fat when it is used for energy. One of the major principles of a protein diet is that the body is required to use fat for energy because not enough glucose is supplied by dietary carbohydrate. This same situation occurs every night while we sleep and are not eating anything, so having ketones in the bloodstream is a natural state. The difference is the quantity of ketones in the natural state versus a state of ongoing ketosis. .
A protein diet plan where only carbohydrate is limited, and both protein and fat are eaten as desired to satisfy hunger. This would still lead to some ketone production when fat is used for fuel; however, there is no scientific evidence that this level of ketones would inhibit the appetite enough to prevent ingestion of adequate calories to meet the body's needs. In other words, starvation equals ketones, but ketones do not equal starvation. Additionally, it is likely that the major appetite control in an unrestricted protein diet is the hormonal effect of dietary fat on brain neurotransmitters. .
The body needs all of the nutrients that supply energy: fats, proteins, and carbohydrates. Each have a unique purpose and are essential in the right amounts, and taxing to the body in the wrong amounts. Too much of any of these nutrients will lead to an increase in body fat. For people who are following a reduced calorie to lose weight, the protein intake should be at least 75 grams per day. This is a higher protein level than the typical intake of a diet that supplies calories to maintain weight. This is because when energy balance is negative (i.e. fewer calories taken in than are needed, causing weight loss), the body's nitrogen requirement is greater to maintain nitrogen balance when other sources of energy (fat and carbohydrate) are not enough to provide energy balance. This amount of protein can be adequately supplied with a reduced calorie diet (of more than 1000 Calories) comprised of 15-20% of calories as protein.
