Fat vs Protein: Which One is Better for Appetite Control and Satiety?
The foods that we choose to eat all have an effect on our health in some way. Our appetites vary from person to person and are influenced by sensations of hunger, our ‘learned’ patterns of eating and eating behaviour, our attitudes toward food and our particular food preferences. The types and levels of certain macronutrients that we consume also play an important role in appetite control.
Studies investigating the relationship between high-fat diets and appetite control have found mixed results. A study conducted in 2000 found that polyunsaturated fats (e.g. from fish) promoted stronger satiety compared to monounsaturated or saturated fats. It did this by decreasing a certain hunger hormone called MCH and thus seemed to delay the return of hunger pangs [1]. In line with these findings, another study uncovered that unsaturated fats (e.g. from nuts and avocado) can effectively curb feelings of hunger and increase fullness through the stimulation of OEA (a fat messenger) [2].
Note: that saturated fats have had a reputation for being ‘bad’ fats (because of a suspected relationship between over-consumption and heart disease). Saturated fats that seem to be on the “cautionary list” are those found mainly in animal meats and products (butter, cream, cheese). Saturated fats typically are solid at room temperature and the term saturated comes from their composition. Coconut oil, a saturated plant oil, although also deemed a saturated fat is the one consistent exception where a body of evidence links it’s consumption to health benefits.)
However, another study disputed this by stating that fat has a weaker effect on appetite control than other macro-nutrients like protein and carbohydrates [3]. What we do know is, the most important thing about fat is the type of fat that is being ingested. Unmodified plant fats tend to be healthiest. Unsaturated fats are more beneficial for health and are more effective at promoting satiety.
Now let’s consider protein. There is an abundance of research and evidence out there that shine a light on protein for the management of appetite and feelings of fullness. One such study is particularly interesting – when protein intake was increased from 15% to 30% over a period of 12 weeks, satiety levels increased significantly. In addition, body weight decreased by about 4.9kg, body fat by 3.7kg and random energy intake (snacking) was lowered by about 450 calories per day [4]. These results look pretty good for the amount of work that is needed. Another study found that eating a high-protein snack in the afternoon such as a yogurt will improve appetite control and decrease the amount of calories eaten for dinner (compared to when snacking on crackers or chocolate) [5].
We have two main hunger hormones working in our body – Leptin and Ghrelin. Leptin decreases appetite while ghrelin will increase it. Research has also revealed that a high-protein diet can suppress the ghrelin hormone more effectively than a high-fat diet, meaning lowered hunger levels!
To conclude, chances are that you can use protein in your diet to help with satiety. You will notice that if you have had too little protein and you increase it you will start to see some changes in how effectively you can manage your appetite and a difference in how full you feel after each meal. If you prefer to eat a higher amount of fat than protein, make sure it’s coming predominantly unsaturated sources like avocados, nuts, seeds, oils and fish or predominantly from plants.
References:
[1] Lawton, L., Delargy, J., Brockman, J., Smith, C., & Blundell, E. (2000). The degree of saturation of fatty acids influences post-ingestive satiety. BrJ Nutrition, 83: 473-482.
[2] University of California. (2008). How fatty foods curb hunger. Science Daily. Retrieved from http://www.sciencedaily.com/releases/2008/10/081007123647.htm
[3] Bludell, J., Lawton, C., Cotton, J., Macdiarmid, J. (1996). Control of human appetite: implications for the intake of dietary fat. Annual Review of Nutrition, 16: 285-319. Retrieved from http://www.annualreviews.org/doi/abs/10.1146/annurev.nu.16.070196.001441?journalCode=nutr
[4] Weigle et. Al. (2005). A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutrition, 82(1): 41-48. Retrieved from http://ajcn.nutrition.org/content/82/1/41.full
[5] Ortinau, H., Hoertel, H., Douglas, S., & Leidy, H. (2014). Effects of high-protein vs. high- fat snacks on appetite control, satiety, and eating initiation in healthy women. Journal Nutrition. Retrieved from http://www.nutritionj.com/content/13/1/97
