Here's How a High Protein Diet Aids Weight Loss

by Amy Hendel, P.A. Health Writer

The Atkins diet was probably the first mainstream commercial diet identified as a high protein diet. Individuals who subscribed to the diet were happy to report substantial weight loss in relatively short periods of time. One caveat was that many in the health community felt it was a dangerous diet because the original version was way too high in saturated fats and forced individuals to limit even fruits and vegetables because of their carbohydrate composition. A newer version of Atkins, along with other higher protein diets like the Paleo diet, are still trending strong because they hasten weight loss. A study, presented at the Society for Endocrinology annual conference in Nov. 2016, explains “how and why” high protein diets help with weight loss.

Researchers from Imperial College London in the UK suggest that phenylalanine, a specific amino acid produced during digestion of protein, seems to boost levels of GLP-1, a satiating hormone. If you feel full, and you stay feeling full longer, you will likely consume fewer calories.

The researcher performed a series of studies on mice and this by-product of protein digestion. In the first study, 10 mice and rats were given a single dose of phenylalanine and compared to a group of rodents who did not receive the dose. They noted higher levels of GLP-1 in the rodents that received the amino acid dose. Not only was GLP-1 higher in the group, but levels of ghrelin, a hormone that increases hunger, were lower. The researchers also noted that the group that received phenylalanine reduced their food intake, lost weight, and also moved around a lot more compared to the control group. That “movement” may also have nudged weight loss.

The next study took a group of mice that were obese, thanks to an obesity-inducing diet. This group received regular doses of phenylalanine over a seven-day period. Compared to an obese control group that did not receive the amino acid dosing, the group lost weight.

In a final study, the researchers applied phenylalanine to cells from the gut in a petri dish in a lab setting. They found that the amino acid seemed to target a receptor in cells called CaSR (calcium-sensing receptor) and this receptor was directly responsible for the rise in GLP-1 levels and reduction in ghrelin levels.

These three studies suggest a feasible way to instigate weight loss. The researchers would like to replicate their findings with testing on humans. Until then, it may be reasonable to increase protein levels in the diet following certain guidelines. Protein sources vary in cost and in the types of nutrients and fats they contain. A diet high in red meat, which is costly and full of artery-clogging fats, is not a good dietary choice. A better goal is to consume a variety of proteins including beans, nuts, seeds, fish, lean meats, skinless poultry, eggs, egg whites, protein powder, high protein grains like quinoa, and higher protein cereals.

We can all benefit from including a bit more protein in our daily diet. One menu outline could be:

Breakfast: One whole egg plus one egg white, one whole grain piece of toast, one or two pieces of fruit, one serving of milk.

AM snack: Cut up veggies with hummus dip.

Lunch: A large garden salad with beans and a small scoop of quinoa, plus half a cup of fruit.

PM snack: A portion of nuts around 100-140 calories, plus a small fruit.

Dinner: A dinner salad, serving of protein (4-6 ounces), 1/2 cup serving of a whole grain, a large serving of steamed vegetables, and serving of fruit. If you do want to significantly increase your protein intake, talk to your doctor. Certain patients may need to restrict protein due to kidney disease. Kids should follow certain protein guidelines based on age and size. It’s also important to outline a healthy and balanced diet plan when targeting weight loss or when you are just trying to maintain a healthy weight.

Amy Hendel, P.A.
Meet Our Writer
Amy Hendel, P.A.

Known as "The HealthGal", Amy Hendel P.A. is a medical and lifestyle reporter, nutrition and fitness expert, health coach and brand ambassador. Trained as a physician assistant, she maintains a health coach private practice in New York and Los Angeles. Author of The Four Habits of Healthy Families, find her on Twitter @Healthgal1103 and on Facebook @TheHealthGal. Check “Daily Health News” at Her personal mantra? “Fix it first with food, fitness, and lifestyle.”