The Carnivore Diet (CD) restricts intake solely to animal-derived products, such as meat, fish, eggs, and certain dairy. This approach removes all carbohydrates, including fruits, vegetables, and grains. While the diet can be an effective weight management tool, the premise that eliminating carbohydrates prevents weight gain is a common misconception. Weight gain on a Carnivore Diet is possible and is governed by basic physics and human metabolism.
The Fundamental Rule of Weight Management
The primary factor determining whether a person gains or loses body fat is the principle of energy balance, often summarized as “calories in versus calories out.” Body weight changes only when energy intake does not equal energy expenditure over a sustained period. If the energy consumed through food exceeds the energy the body uses for daily functions, the surplus energy must be stored, regardless of the source.
When a positive energy balance occurs, the body converts excess fuel into stored energy, predominantly as body fat. This process applies universally to every eating pattern, including the Carnivore Diet. Whether the extra energy comes from fat, protein, or alcohol, consistent overconsumption results in weight gain.
In a state of positive energy balance, approximately 60 to 80 percent of the resulting weight gain is attributable to the accumulation of body fat. Although metabolic pathways may differ without carbohydrates, they converge on the same storage mechanism. Any diet can lead to fat accumulation if the total caloric intake is high enough.
Some individuals experience initial weight loss on the Carnivore Diet because high protein and fat content promote satiety, reducing overall calorie intake. However, this effect does not override the energy balance equation if overeating occurs consistently. If energy intake is too high, weight gain is the predictable biological response.
How High-Fat Choices Contribute to Calorie Density
A caloric surplus can be achieved on the Carnivore Diet due to the calorie density of the allowed foods. Fat is the most concentrated source of energy, providing nine calories per gram, more than double the four calories per gram provided by protein. Since the diet relies heavily on animal products, the choice of cut and preparation method significantly impacts total energy intake.
Selecting fattier cuts of meat, such as ribeye steak or high-fat ground beef, versus leaner options like sirloin, increases the calorie count of a meal. A 4-ounce serving of lean beef is lower in calories than the same weight of a marbled cut. This difference means a person can consume a large volume of food that feels satisfying, yet still unknowingly over-consume calories.
Many adherents of the Carnivore Diet add pure animal fats to their meals for energy and satiety. The common addition of butter, tallow, or lard to cook and season meals rapidly elevates the diet’s energy density. Even small additions of these concentrated fats can push a person into a caloric surplus without noticeably increasing the physical volume of the meal.
If full-fat dairy products like heavy cream or cheese are included, they represent a further source of dense calories. Their high fat content makes it simple to consume excess energy without feeling overly full. The ability to consume a large amount of energy in a small quantity of food is why a caloric surplus is attainable on this diet.
The Metabolic Impact of Protein and Fat
The body processes and stores energy from both fat and protein, even when carbohydrates are absent. Dietary fat, consumed as triglycerides, is incorporated into the body’s adipose tissue. When excess fat is eaten, it requires minimal metabolic conversion before being stored as body fat, making it the most direct contributor to fat gain when intake exceeds energy needs.
Excess protein is not simply eliminated; it enters a metabolic pathway that can still contribute to fat storage. When protein intake exceeds the amount required for tissue repair and maintenance, the amino acids are processed in the liver. A portion of these excess amino acids can then be converted into glucose through gluconeogenesis.
Gluconeogenesis ensures the body receives the small amount of glucose it requires, even on a zero-carbohydrate diet. This newly created glucose can be used for immediate energy, but if it remains in surplus, it enters the general energy pool. Ultimately, this excess energy, whether derived from protein or fat, can be stored as body fat, creating the potential for weight gain.