Can a Protein-Packed Breakfast Help You Feel Fuller and Sharper?
We've all heard the saying, "Breakfast is the most important meal of the day." But does science back this up, and does it matter what you eat for breakfast? A recent study explored these questions, specifically looking at the impact of a high-protein breakfast on young women who were overweight or had obesity. Let's break down what they found and what it means for you.
The Study Setup: What Did They Do?
The researchers recruited young women aged 18-30 who were either overweight or had obesity. They wanted to see if a high-protein breakfast was more effective at making people feel full (satiated) compared to a typical lower-protein, higher-carb breakfast or skipping breakfast altogether. 1.2.
Here's how the study worked:
The women participated in three different "experimental days," with at least one day of break in between. 3.
On each of these days, they were randomly assigned to eat one of three breakfasts:
High-protein, low-carb (PRO): This breakfast contained about 32 grams of protein, mainly from a dairy source (like Greek yogurt).
Low-protein, high-carb (CHO): This was your more traditional breakfast, containing about 5 grams of protein, with foods like toast and jam.
No breakfast (CON): For this option, the participants only had water.
The researchers carefully matched the calorie, fibre, and fat content of the PRO and CHO breakfasts, so the only major difference was the amount of protein.
Throughout the day, the researchers measured several things:
Appetite: The women rated their feelings of hunger, fullness, and satisfaction at different times using special questionnaires.
Food Intake: They had a large lunch of lasagna provided three hours after breakfast, where they could eat as much as they wanted. The researchers measured how much they ate. The women also recorded all the other foods they ate for the rest of the day.
Hormones: The researchers took blood samples to measure levels of hormones related to appetite, like ghrelin and GLP-1.
Cognitive Function: The women took a concentration test two and a half hours after breakfast.
The Results: What Did They Find?
The study yielded some intriguing results:
Feeling Full and Fighting Hunger:
Women who ate the high-protein breakfast (PRO) reported feeling significantly more full (satiated) and less hungry in the hours after breakfast compared to those who ate the low-protein (CHO) breakfast or skipped breakfast altogether (CON).
These feelings of fullness and reduced hunger were especially noticeable between 10 minutes and 170 minutes after eating breakfast.
Lunchtime and Total Calories:
Surprisingly, even though the PRO group felt fuller for longer, they didn't end up eating less lasagna at lunch than the other groups.
Their total calorie intake for the entire day was also similar across all three breakfast groups.
Hormones and Hunger Signals:
The researchers didn't find any major differences in the levels of appetite-regulating hormones (like ghrelin and GLP-1) between the breakfast groups.
Brainpower Boost:
The women who ate the high-protein breakfast (PRO) performed better on the concentration test compared to those who skipped breakfast (CON).
There was no difference in cognitive performance between the high-protein (PRO) and low-protein (CHO) breakfast groups.
Making Sense of It All: What Does It Mean?
This study provides some interesting food for thought, but it also leaves us with some questions.
The Protein-Satiety Puzzle:
The big question is why the increased feelings of fullness after the high-protein breakfast didn't translate into eating less food later in the day. There are a few possible explanations:
Habit: People often get into a routine of eating a certain amount at mealtimes. It's possible that this habit of eating a certain amount at lunch overrode the differences in how full the women felt.
Study Design: The women had to eat lunch at a fixed time, whether they were hungry or not. If they had been allowed to eat when they felt hungry, the PRO group might have naturally delayed their lunch and eaten less overall.
Other Factors: The study participants tended to have eating habits influenced by external cues, like the time of day or what food was available, rather than just their internal hunger signals. This could have also played a role in their food intake.
The Protein-Brainpower Connection:
The finding that a high-protein breakfast enhanced concentration is promising. It supports the idea that what you eat for breakfast can impact your mental performance. However, more research is needed to confirm this effect and understand the mechanisms behind it.
Key Takeaways: What Can We Learn?
While this study doesn't give us all the answers, it highlights some important points:
Protein and Fullness: A protein-rich breakfast can help you feel fuller and more satisfied for longer, which is beneficial for managing hunger and cravings.
Protein and Brainpower: A protein-packed breakfast might give your brain a boost, potentially improving your concentration and focus.
Long-Term Effects: More research is needed to see if these short-term benefits of a high-protein breakfast translate into long-term weight management or sustained improvements in cognitive function.
It's worth noting that the study focused on young women who were overweight or had obesity. While the findings are interesting, we need more research to know if they apply to other groups, such as men, people of different ages, or those with different weight statuses.
This study gives us a glimpse into the potential benefits of a high-protein breakfast, but it's just one piece of the puzzle. Ultimately, the best breakfast for you will depend on your individual needs and preferences. If you're looking to feel fuller for longer and possibly enhance your mental sharpness, adding more protein to your morning meal might be a good place to start.
ABSTRACT
The purpose of this study was to investigate if con-sumption of a high-protein, low-carbohydrate breakfast (PRO) leads to a lower subsequent ad libitum energy intake at lunch and the rest of the day compared with ingestion of an isocaloric low-protein, high-carbohy-drate breakfast (CHO) or no breakfast (CON). The study was designed as a randomized controlled 3-period crossover study. Thirty young (18–30 yr) females with overweight to obesity (body mass index >25 kg/m2) in random order completed 3 separate experimental days where they consumed either a PRO, CHO, or CON breakfast test meal followed by an ad libitum lunch meal 3 h after breakfast. Participants were allocated to a sequence group by their inclusion number. The PRO and CHO breakfasts were matched in dietary fiber and fat content. Energy intake at lunch was calculated and dietary records were obtained for the rest of the day to calculate the total daily energy intake and macronu-trient intake. Ratings of appetite sensations between meals and palatability of the test meals were assessed using visual analog scale sheets in intervals ranging from 10 to 30 min. In addition, blood samples were obtained at multiple time points separated by 10 to 60 min intervals between breakfast and lunch and were analyzed for appetite-regulating gut hormones, insulin, and glucose. Finally, performance in a cognitive concen-tration test was tested 150 min after breakfast. Com-pared with CHO and CON, the area under the curves for satiety, fullness, and satisfaction in the 3 h after breakfast were significantly higher after PRO, whereas the areas under the curve for hunger, desire to eat, and prospective eating were significantly lower after PRO. The appetite-regulating gut hormones cholecystokinin, glucagon-like peptide-1, and ghrelin in the hours after
MATERIALS AND METHODS
Participants
Young (18–30 yr), females with overweight to obesity (BMI >25 kg/m2) were recruited through social me-dia and posters in the local city of Aarhus, Denmark. Eligibility was assessed by an online questionnaire (Supplemental Table S1; https: / / figshare .com/ articles/ online _resource/ Supplementary _Files/ 24042975/ 5; Kruse, 2023) and exclusion criteria were pregnancy, food allergies, needle phobia, mental diseases, chronic and metabolic diseases, use of medication that affects appetite, physical training >5 h/wk, >5 kg weight change in the previous 6 mo, irregular menstrual cycle, not liking lasagna, or participation in other research studies including diet intervention or blood sampling. Eligible females went through a telephone screening, and if accepted, a meeting was scheduled for further information and measurements of height, weight, body composition, and habituation to the cognitive test. All participants provided written consent before any data was collected. In total 58 females were included in the randomization and 30 completed the experimental period. A consolidated standards of reporting trials (CONSORT) flow diagram of the number of partici-pants from the start of inclusion to the final analyses is shown in Figure 1. Subject characteristics are shown in Table 1. The study was conducted in accordance with the Declaration of Helsinki, approved by the Central Denmark Region Committees on Health Research Eth-ics (journal no. 1–10–72–220–19), and was registered at Clininal.trials.gov (ID: NCT04652713).