When Is The Best Time To Consume Protein?
About Scott V Watkins, MD
A second important part of the Protein Leverage Hypothesis, as detailed in Part 1 of the “Lack of Protein Drives Hunger” Learning Centre post, illustrates the importance of WHEN we consume our protein.
Most of my readers know I am a big fan of Intermittent Fasting, so equate your “first meal” with when you break your fast — and that’s not necessarily the morning breakfast.
The Australian study published in Obesity looked at three structured eating periods corresponding essentially to breakfast, lunch, and dinner (the evening meal). This study specifically evaluated the amount of protein consumed with the first meal of the day and what that meant for the rest of the day in regard to eating. Evaluation of the amount of protein consumed was based on the Acceptable Macronutrient Distribution Range (AMDR) and participants were separated into three groups based on the amount of protein they ate with their first meal:
Energy Intake from protein with the first meal:
- Less than 15% protein, below the AMDR.
- 15-25% protein, within the AMDR.
- More than 25% protein, above the AMDR.
The daily intake of calories/energy was then plotted. The study participants who had less than 15% of their first meal as protein ate more calories throughout the day, in essence, still looking to fulfill that protein hunger. Those participants who ate the first meal of 15% to 25% protein had moderate caloric intake throughout the day. They were satisfying their protein hunger during the day and thus were not driven to consume more. Those who had more than 25% protein with the first meal actually reduced their caloric intake through the day to keep their total protein intake within range, and thereby ate less of everything else (carbs and fats).
Further studies looking at the daily distribution of protein seem to confirm that 3 meals each containing 25-30 gm of high-quality protein is best for stimulating muscle protein synthesis in adults.
To read more on studies shedding light on this area, click on these links:
- Dietary protein recommendations and the prevention of sarcopenia.
- Moderating the portion size of a protein-rich meal improves anabolic efficiency in the young and elderly.
- Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults.
- Per meal dose and frequency of protein, consumption is associated with lean mass and muscle performance.
- Even mealtime distribution of protein intake is associated with greater muscle strength, but not with 3-y physical function decline, in free-living older adults.
Additional trials have looked at large variations in protein distribution (7% of protein in the first meal, 79% in the second meal, and 14% in the third). A study reported in 1999 in the American Journal of Clinical Nutrition did show an improved nitrogen balance in the research participants, but they didn’t reach the 25-30 gm of high-quality protein at each meal that seem better to stimulate muscle growth/maintenance. Interpreted in light of the study that evaluated the amount of protein consumed at the first meal — and how it drives our protein hunger and calorie consumption throughout the day — it does not seem wise to have the first meal of the day made up of only 7% protein, as this will create more protein hunger during the day.
This ties in nicely with an additional phenomenon we see in Western diets: We tend to consume much more protein at the end of the day (evening meal). Again referring to data from the U.S. National Health and Nutritional Examination Survey (NHANES), women consume approximately 30% of their protein at their evening meal, while men consume 43.5%. This data is from 2006, but as all of our other dietary parameters have worsened over the years, it doesn’t seem plausible that this trend has improved.
I have heard an older person say that we should “eat breakfast like a king, lunch like a prince, and dinner like a pauper.” The studies seem to align with that rationale but do not appear to represent what we actually do. Muscle mass is essential for a variety of health and aging issues, and we need to maintain adequate protein intake throughout our lives. And the amount of protein we need may actually increase with age as we become less able to process food and calories, and when muscle loss accelerates.
In our next article, we will review some of the sources of protein, which do go beyond red meat!
Lack of Protein Drives Hunger (Part 2)
