Study Reviewed: No Effect of Breakfast Consumption Observed for Afternoon Resistance Training Performance in Habitual Breakfast Consumers and Nonconsumers: A Randomized Crossover Trial. Stratton et al. (2023)

Breakfast can be defined a couple different ways. In the most literal sense, it is the first meal of the day that involves breaking the overnight fast. In a more colloquial sense, breakfast refers to a meal that occurs in the morning, most commonly within a couple hours of waking. Growing up in America, I was constantly reminded that breakfast was the most important meal of the day because it helps you start your day with a healthy boost of nutrients and energy. Is this cliché rooted in science, or is it just a marketing slogan to sell breakfast cereals?

A new study by Stratton and colleagues (1) sought to determine if “skipping breakfast” impacts training performance during afternoon workouts. I put “skipping breakfast” in quotation marks to reflect the fact that it’s a bit of an oxymoron if you adopt a literal definition of breakfast. If breakfast is the first meal that breaks the overnight fast, then you can’t technically skip it – you can only delay it. Nonetheless, we’re talking about a study investigating the impact of skipping the morning meal and shifting those calories to lunch. Participants included 39 resistance-trained adults (20 men, 19 women) between ages 18-40. In order to participate, subjects needed to be generally healthy and resistance trained (defined as completing at least two workouts per week for at least three months prior to participation). In addition, participants needed to bench press at least 0.5x (females) or 1.0x body mass (males), barbell back squat at least 0.75x (females) or 1.375x (males) body mass, and conventional barbell deadlift at least 1.0x (females) or 1.75x (males) body mass. Approximately half of the participants routinely (5+ days per week) consumed breakfast in the morning, while the other half did not consume breakfast in the morning. 

The study consisted of three lab visits separated by 3-10 days. The first visit consisted of screening, maximal strength testing, and body composition testing. The second and third lab visits were testing sessions where participants either did or did not consume breakfast prior to their workout. The workout consisted of four sets each of squat, bench press, and deadlift with 80% of 1RM; the first three sets were terminated with one repetition in reserve, and the fourth set was taken to failure. This was a crossover trial, meaning that participants completed both experimental conditions and essentially served as their own “control” subject. In the breakfast condition, participants were given two meals providing 40% of their predicted daily energy expenditure (15% at breakfast, 25% at lunch). Breakfast was consumed 4.5-7 hours before the afternoon exercise session, and lunch was consumed 1.5-3 hours before the workout. On average, breakfast was consumed 6 hours before the workout and lunch was consumed 2.5 hours before the workout. In the breakfast skipping condition, participants were given a single meal providing 40% of their predicted daily energy expenditure, which was consumed 1.5-3 hours before the workout. In short, the breakfast skipping condition involved eating the same amount of total food and eating lunch at the same time (no breakfast and a big lunch instead of a smaller breakfast and smaller lunch). Outcomes of interest included repetitions completed, bar velocity outcomes, and subjective feelings of fatigue, energy, focus, hunger, desire to eat, and fullness throughout each exercise session.

The researchers did not find a significant effect of condition (breakfast versus no breakfast) on repetitions performed. Figure 1 shows the total repetitions per set (combining squat, bench, and deadlift), but the results for individual exercises were similar. Results did not differ among people who do or do not habitually consume breakfast. Similarly, the researchers did not find a significant effect of condition (breakfast versus no breakfast) on bar velocity or power outcomes. Figure 2 shows average concentric velocity combined across all exercises and repetitions, but the results were similar for all bar velocity and power outcomes. Once again, results did not differ among people who do or do not habitually consume breakfast. For performance-related outcomes, the only significant effects were sex-related and indicated that males had higher power output but experienced greater fatigue during testing. For subjective outcomes, participants reported higher fullness when they skipped breakfast, which makes sense given that fullness was assessed after they consumed a substantially larger lunch. Males reported greater decreases in energy and greater increases in hunger and desire to eat throughout the exercise session, but these outcomes were not impacted by condition (breakfast versus no breakfast) or habitual breakfast consumption.

In summary, skipping breakfast didn’t meaningfully impact performance or subjective outcomes of an afternoon training session, aside from greater feelings of fullness. Of course, there are a few important caveats to keep in mind. First, the total amount of food consumed was equated in both conditions; if someone’s breakfast-skipping habit substantially reduced their total pre-workout calorie intake, results could differ. Second, the workout occurred about 2.5 hours after lunch. If breakfast skippers try to train before lunch, they may very well experience performance impairments. On the other hand, if breakfast skippers eat an enormous lunch immediately before their workout, performance could be negatively impacted by excessive fullness and gastrointestinal discomfort. Now, to facilitate interpretation, I’d like to highlight a few practical notes related to breakfast skipping.

First, breakfast skipping is a viable strategy for weight reduction. This is an area of considerable debate and misunderstanding because of discrepancies between observational and experimental research on the topic. Observational studies tend to find that people who skip breakfast are more likely to have BMIs in the overweight or obese category (2). However, we should always hesitate before assuming that this type of correlation implies a causative relationship between breakfast skipping and increased adiposity. In experimental trials, researchers often find that individuals who are instructed to skip breakfast end up eating slightly more at later meals, but fewer total calories throughout the entirety of the day (3). Along these lines, a 2019 meta-analysis of randomized controlled trials by Sievert et al (4) found that skipping breakfast led to small but statistically significant reductions in body weight (around half a kilogram) and total daily energy intake (around 260 kcal/day) compared to eating breakfast. In summary, the data suggest that breakfast skipping is a totally defensible strategy to facilitate weight loss goals, and that breakfast skipping won’t necessarily impair afternoon resistance training that occurs in a fed state (1).

Second, if you experiment with breakfast skipping, try not to train hungry. Dr. Helms has covered this topic extensively (one, two, three), so I’ll just summarize the key takeaways in this Research Brief. In one study (5), researchers tested squat and bench press repetitions to failure two hours after habitual breakfast consumers ingested a breakfast or water only. Results indicated that participants completed more repetitions when they consumed breakfast instead of skipping it. In a second study (6), the same researchers added a wrinkle to their study design by introducing a viscous, semi-solid placebo with very low energy intake. This time around, they found that eating a placebo sludge restored performance to the same degree as a carbohydrate-based breakfast, leading them to conclude that breakfast skipping impairs performance due to increased hunger rather than insufficient energy or nutrient availability. The same group of researchers published a third study (7), this time comparing liquid versus semi-solid breakfasts with similar nutrient and energy content. Participants completed more reps in the semi-solid breakfast condition, in addition to reporting higher fullness and lower hunger. So, if you’re going to use breakfast skipping as part of a weight management intervention and you want to preserve your performance in the gym, try to eat at least enough to curb your hunger before diving into your afternoon or evening workout.

Third, the presently reviewed study adds to the literature indicating that 16:8 time-restricted feeding (that is, a daily fasting window of 16 hours with an 8-hour feeding window) is a very viable eating pattern for lifters. I’ve previously stated that an 8-hour feeding window should facilitate satisfactory gains, as long as you’re checking a few very simple boxes: eat enough total protein, split your protein across ~3-4 servings within your 8-hour feeding window, and train in a fed state. Randomized controlled trials by Tinsley et al (8) and Moro et al (9) generally reinforce this strategic approach to time-restricted feeding. While a much longer study suggests that time-restricted feeding could actually attenuate lean mass gains (10), the findings are confounded by a very important detail: the time-restricted feeding group was in an energy deficit, while the standard diet group was in an energy surplus. Based on the totality of the literature, I think an 8-hour feeding window is a totally defensible approach for lifters, and in many cases, 16:8 time-restricted feeding is a fancy name for skipping breakfast.

References

1. Stratton MT, Siedler MR, Rodriguez C, Harty PS, Boykin JR, Keith DS, Green JJ, White SJ, Tinoco E, DeHaven B, VanDusseldorp TA, Tinsley GM. No Effect of Breakfast Consumption Observed for Afternoon Resistance Training Performance in Habitual Breakfast Consumers and Nonconsumers: A Randomized Crossover Trial. J Acad Nutr Diet. 2023 Sep 22:S2212-2672(23)01561-7.
2. Ma X, Chen Q, Pu Y, Guo M, Jiang Z, Huang W, Long Y, Xu Y. Skipping breakfast is associated with overweight and obesity: A systematic review and meta-analysis. Obes Res Clin Pract. 2020 Jan-Feb;14(1):1-8. doi: 10.1016/j.orcp.2019.12.002.
3. Levitsky DA, Pacanowski CR. Effect of skipping breakfast on subsequent energy intake. Physiol Behav. 2013 Jul 2;119:9-16. doi: 10.1016/j.physbeh.2013.05.006.
4. Sievert K, Hussain SM, Page MJ, Wang Y, Hughes HJ, Malek M, Cicuttini FM. Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials. BMJ. 2019 Jan 30;364:l42.
5. Bin Naharudin MN, Yusof A, Shaw H, Stockton M, Clayton DJ, James LJ. Breakfast Omission Reduces Subsequent Resistance Exercise Performance. J Strength Cond Res. 2019 Jul;33(7):1766-1772.
6. Naharudin MN, Adams J, Richardson H, Thomson T, Oxinou C, Marshall C, Clayton DJ, Mears SA, Yusof A, Hulston CJ, James LJ. Viscous placebo and carbohydrate breakfasts similarly decrease appetite and increase resistance exercise performance compared with a control breakfast in trained males. Br J Nutr. 2020 Mar 16:1-9.
7. Naharudin MN, Yusof A, Clayton DJ, James LJ. Starving Your Performance? Reduced Preexercise Hunger Increases Resistance Exercise Performance. Int J Sports Physiol Perform. 2022 Mar 1;17(3):458-464.
8. Tinsley GM, Moore ML, Graybeal AJ, Paoli A, Kim Y, Gonzales JU, et al. Time-Restricted Feeding Plus Resistance Training In Active Females: A Randomized Trial. Am J Clin Nutr. 2019 Sep 1;110(3):628–40.
9. Moro T, Tinsley G, Bianco A, Marcolin G, Pacelli QF, Battaglia G, Palma A, Gentil P, Neri M, Paoli A. Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. J Transl Med. 2016 Oct 13;14(1):290.
10. Moro T, Tinsley G, Pacelli FQ, Marcolin G, Bianco A, Paoli A. Twelve Months of Time-restricted Eating and Resistance Training Improves Inflammatory Markers and Cardiometabolic Risk Factors. Med Sci Sports Exerc. 2021 Dec 1;53(12):2577-2585.