Dietary proteins stimulate Cholecystokinin or CCK secretion, a hormone in the brain and gut, to start the secretion of pancreatic enzymes, gallbladder contractions, intestinal motor activity and stop the stomach from emptying. When CCK gets released in the gut you reduce your food intake and your meal size and you feel full. We really need a side of CCK instead of a side of fries.
High protein diets increase plasma amino acid concentrations in the blood. This creates a vagal nerve feedback signal to the nucleus tractus solitarius in the brainstem and hypothalamus to make you feel full. Compared to carbs and fats you can't get this same response.
The liver makes usable glucose (gluconeogenesis) for energy and to maintain plasma glucose levels. To do this, two key enzymes, PEPCK and G6P, are needed. Gluconeogenesis is stimulated by a high protein diet. When you eat a high protein diet you produce ketone bodies which suppress the appetite.
When you are losing weight you need high protein intake to preserve your lean body mass. When we eat you secrete insulin to breakdown that incoming food. Insulin prevents fat cells from burning. A meta analysis of 18 randomized controlled trials found older adults (above 50 +) preserved lean body mass during weight loss by eating a high protein diet.
We need some carbs for strength and endurance performance, but if you are overweight you want to choose a good protein source over carbs because carbs prevent you from burning fat. Low carb high protein diets prevent fat tissue from developing.
215 obese subjects were studied for 12 weeks comparing high protein to standard protein diets. Those in the high protein diet group had lower cholesterol and triglycerides and better weight control.
Once thought to be a problem with bone breakdown, high protein diets favor intestinal calcium uptake and improve bone mineral density. If you are prone to forming kidney stones you can easily balance your high protein intake with alkali-forming fruits and vegetables to balance your acid/alkaline balance. I test patients for kidney function when we move to high protein diets. Second Nature patients take 1/4 tsp. of baking soda dissolved into 8 oz. of water and drink this 2-3 times per day as added insurance against acid build-up.
The jury is in. Choose your proteins wisely and shift to a high protein, low carb and not in excess, but good quality fats in your diet.
Here some other high protein choices besides meat. Second Nature Care has answers to your weight loss questions.