If you have milk, cheese or Greek yoghurt for breakfast, then you might just be onto a winner.
Researchers recommend that eating a large breakfast containing whey protein, followed by a medium-sized lunch and small dinner could be best for people looking to lose a few pounds.
In a small study of 48 overweight people, whey protein helped participants feel fuller for longer and reduced blood sugar spikes too.
"A high-calorie protein breakfast, medium-sized lunch and small dinner is a proven successful strategy for weight loss, improved satiety and reduced glucose spikes throughout the day in people with obesity and Type 2 diabetes," said lead study author Daniela Jakubowicz, professor of medicine at Tel Aviv University.
"However, the benefits of high protein content at breakfast also depend on the protein source and quality.
"Whey protein powder, which is a byproduct of milk during cheese production, induced greater satiety and reduction of glucose spikes after meals compared to other protein sources, such as eggs, soy or tuna."
Dairy products such as milk, cheese and Greek yogurt are the best sources of whey protein.
Researchers wanted to investigate whether, in overweight and obese people with Type 2 diabetes, whey protein for breakfast was more effective than other proteins for weight loss, satisfaction and reduction of glucose spikes and HbA1C (glycated hemoglobin) levels.
They randomly assigned 48 overweight and obese participants with Type 2 diabetes who were, on average, 59 years of age, to one of three diets that contained the same number of calories.
For 23 months, all participants ate a large breakfast, medium-sized lunch and small dinner, but the breakfast composition, amount and source of proteins differed among the groups.
One group ate breakfast containing mostly whey protein such as whey protein shakes, the second group ate breakfast containing other proteins including eggs, soy and tuna, and the third ate breakfast high in carbohydrates or starch.
After 12 weeks, the group on whey protein lost the most weight.
On average, they lost 7.6 kg (16.7 pounds), compared to 6.1 kg (13.4 pounds) for those eating other proteins, and 3.1 kg (6.8 pounds) for those in the carbohydrate group.
Whey protein diet participants felt full for longer, with lower glucose spikes after meals compared to the other two diets.
Jakubowicz said: "The whey protein diet significantly suppresses the hunger hormone 'ghrelin'.
"A whey protein drink is easily prepared and provides the advantages of a high-protein breakfast on weight loss, reduction of hunger, glucose spikes and HbA1c."
The study results were presented at ENDO 2016, the annual meeting of the Endocrine Society, in Boston.