Reasons Why You Should Pack your Meals with Optimal Amounts of Protein Throughout the Day
I know that is has been awhile since I've posted on my blog, but what can I say life is busy and this past spring has been full of academic celebrations, weddings, and travel to scientific conferences. Needless to say, I'm back at it and working to provide my readers with some nutrition focused and science-worthy information. The topic of this month's blog post is protein. Perhaps you've already heard that protein is an essential nutrient in the diet that helps us build, repair and maintain body tissues, but maybe you aren't familiar with the science around protein quality, timing of protein intake, and how much protein we should be getting in our diet every single day. While it is impossible for me to highlight all of the recent work done in this area, I thought I'd share some useful information and provide you with some practical tips on how to get adequate amounts of protein in your diet. Trust me, you don't want to miss out on this essential nutrient!
Protein and Breakfast
Is breakfast the most important meal of the day? What happens when we test different breakfasts of equal calories, but vary the protein content? Do you think you'd feel more full? In a randomized crossover trial, a group of researchers aimed to examine whether or not a high-protein compared with a normal-protein breakfast lead to any improvements in appetite, satiety, and evening snacking in twenty overweight or obese breakfast-skipping girls (1). To test this idea, the girls were fed a normal breakfast composed of cereal, equating to about 350 calories and 13 g of protein, a higher protein breakfast composed of an egg and beef-mix, for 350 calories and 35 g of protein, or no breakfast (breakfast skippers) (1). All breakfasts were consumed for 6 consecutive days.
The results from this study were quite interesting. While it is not a surprise that the consumption of breakfast (normal protein or high protein) reduced daily hunger compared with breakfast skippers, the high protein breakfast did cause a greater increase in daily fullness compared to the normal protein breakfast (1). The high protein breakfast also reduced evening snacking of high-fat foods compared with breakfast skippers (1). While I'm only highlighting one study here on protein and breakfast, this data suggests that the addition of breakfast, especially one high in protein, might be a great way to improve satiety and diet quality in a group of overweight or obese girls.
Not all Protein is Created Equal
Protein is made up of building blocks called amino acids and altogether their are 20 of them. These amino acids are further classified as essential and non-essential. Of the 20 amino acids, 11 are non-essential meaning that our body makes these, however the 9 essential amino acids, can't be made by our body, therefore we have to obtain them from our diet every single day. If you are wondering where we get these essential amino acids from, think about high-quality proteins from food sources such as dairy, eggs, lean beef, poultry, pork, and fish (2). Plant sources such as soy and quinoa are also considered high-quality or complete proteins because they provide the essential amino acids our bodies need. Other plant sources, unfortunately, do not provide all of the essential amino acids our bodies need and therefore are considered incomplete proteins.
How Much Protein Do You Need Everyday?
The question of how much protein you need in your diet is a very common one. As a registered dietitian nutritionist, I consider several factors to determine how much protein is needed before making a recommendation to someone. Factors such as age, health status, and level of physical activity should all be considered when deciding how much protein should be included in your diet. For healthy adults, the Institute of Medicine (IOM) has set what is known as a Recommended Dietary Allowance (RDA) for protein. The RDA for protein is 0.8 g/kg body weight per day and this represents the minimum daily dietary nutrient intake level sufficient to meet the nutrient requirements for 97-98% of all healthy individuals in a particular life stage group (3). I stress the word minimum because this means we can go higher. Based on the RDA, a healthy 150-pound woman would require about 54 g of protein, but again this woman is healthy.
A few years ago, international expert groups called for higher protein intakes in healthy and non-healthy older adults (65 yrs. +), due to physiological changes that are associated with aging (4, 5). According to expert group recommendations, healthy older adults should have protein intakes in the range of 1.0-1.2 g/kg body weight per day, whereas older adults with acute or chronic diseases should go even higher at 1.2 to 1.5 g/kg body weight per day. Finally, those older adults suffering from severe illnesses, injuries, or malnutrition can take as much as 2.0 g/kg body weight per day. Now take our same 150-pound woman who is suffering from malnutrition and she may need as much as 136 g of protein each day. These numbers are markedly different and you might be thinking,"How do I really know how much protein I need every single day"? My advice is to work closely with a registered dietitian nutritionist so he or she can help you determine your protein needs for optimal health.
How to Fit Protein Into Your Meals and Snacks
Fitting sources of protein into your diet can be done with some proper meal planning. The first step is to think about getting at least a source of protein in at each meal and snack, trust me spreading your intake out across the day will help you reach your recommended levels. What is the magic number of protein at each meal? Research published by Paddon-Jones and Leidy suggests that older adults should consume between 20-35 g of protein at each meal
to preserve lean body mass and maximize protein synthesis (6). Below you will find a list of protein sources and how much they contain per serving. Choosing these foods at each meal and snack will help you reach the amount of protein that you need every single day.
1/4 cup nuts = 5 g protein
1 large egg = 6 g protein
2 Tbsp. peanut butter = 7 g protein
1 cup (8 fl oz) skim milk = 8 g protein
1 cup black beans = 14 g protein
3 ounces lean, ground beef = 17 g protein
1 container (170 g) plain, nonfat Greek Yogurt = 17 g protein
3 ounces chicken breast = 26 g protein
*Source: USDA National Nutrient Database for Standard Reference Release 28 2016. Accessed May 29, 2017.
1. Leidy HJ, Ortinau LC, Douglas SM, Hoertel HA. Beneficial effects of a higher-protein breakfast on appetitive, hormonal, and neural signals controlling energy intake regulation in overweight/obese, "breakfast-skipping," late-adolescent girls. Am J Clin Nutr 2013;97:677-88.
2. National Dairy Council. Why is Protein Important? 2017. https://www.nationaldairycouncil.org/content/2017/why-is-protein-important. Accessed May 29, 2017.
3. Institute of Medicine of the National Academies. Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington DC. 2002/2005. Accessed May 29, 2017.
4. Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559.
5. Deutz NE, Bauer JM, Barazzoni R, et al. Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group. Clin Nutr. 2014;33(6):929-936.
6. Paddon-Jones D, Leidy H. Dietary protein and muscle in older persons. Curr Opin Clin Nutr Metab Care. 2014;17(1):5-11.