Pros: The most consistently beneficial of all diets here, study after study shows that upping your protein intake can help significantly reduce body fat and build lean muscle. For example: Guys who ran sprint intervals, did resistance training, and ate a diet of 2.4g of protein per kg of bodyweight per day (roughly 1g per lb of bodyweight) gained 1.2kg of lean muscle and lost almost 5kg of fat in just four weeks, according to a study in the American Journal of Clinical Nutrition. If you cut calories but eat high protein, the macro can help prevent your metabolism from plummeting and help keep hunger at bay, since protein is so satiating. The study analysis also confirmed that eating a ton of protein stuff doesn’t cause you to gain weight or harm any internal systems, despite myths.
One downside to a ketogenic diet for weight loss is the difficulty maintaining it. “Studies show that weight loss results from being on a low-carb diet for more than 12 months tend to be the same as being on a normal, healthy diet,” says Mattinson. While you may be eating more satiating fats (like peanut butter, regular butter, or avocado), you’re also way more limited in what’s allowed on the diet, which can make everyday situations, like eating dinner with family or going out with friends, far more difficult. Because people often find it tough to sustain, it’s easy to rely on it as a short-term diet rather than a long-term lifestyle.
Y. Wady Aude, MD; Arthur S. Agatston, MD; Francisco Lopez-Jimenez, MD, MSc; Eric H. Lieberman, MD; Marie Almon, MS, RD; Melinda Hansen, ARNP; Gerardo Rojas, MD; Gervasio A. Lamas, MD; Charles H. Hennekens, MD, DrPH, “The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat,” Arch Intern Med. 2004;164(19):2141-2146. http://archinte.jamanetwork.com/article.aspx?articleid=217514.
The researchers agree that the diet itself isn’t inherently dangerous. But, cautions Weiss, “If you have any medical condition, if you take any medicine at all – there are lots of things that change how medicines work in our bodies, and nutrition is definitely one of them. If you’re making a real change in your nutrition, you really should talk to your doctor.”
People claiming huge benefits of these supplements – despite the lack of solid scientific support – may sometimes have a financial reason to believe in the supplements. Some of these products are sold under a multi-level marketing arrangement, where sales people are paid based on commission. For example, the company Prüvit sells drinkable ketones, called KETO//OS with a multi-level marketing structure.