The effect of breakfast on appetite regulation, energy balance and exercise performance

Blood metabolites mediate effects of breakfast skipping on heart failure via Mendelian randomization analysis

Numerous observational studies have suggested a potential causal relationship between skipping breakfast and cardiovascular diseases, including heart failure (HF). However, these studies are susceptible to inherent confounders and the challenge of reverse causation, and the underlying metabolic factors are not yet clear. Therefore, our aim is to assess the causal impact of breakfast skipping on HF and the role of potential mediating metabolic products from a genetic perspective, by conducting Mendelian Randomization (MR) studies and mediation analysis. We leveraged summary data from the most extensive genome-wide association studies to date on breakfast skipping (with 193,860 participants), blood metabolites (with 118,461 participants), and HF (involving 47,309 cases and 930,014 controls). To explore the causal relationship between breakfast skipping and HF, as well as the role of 249 potential blood metabolite mediators, we conducted bidirectional MR and mediation MR analyses. We primarily employed the Inverse Variance Weighted (IVW) method, complemented by various other techniques to ensure the comprehensiveness and reliability of our analysis. Our research confirms a causal association between breakfast skipping and an increased risk of HF (odds ratio [OR]: 1.378, 95% confidence interval [CI]: 1.047-1.813; p = 0.022). Furthermore, our research findings demonstrate that breakfast skipping is positively correlated with 6 blood metabolites and negatively correlated with 2 others. Notably, our mediation MR analysis further reveals that three blood metabolites act as mediators in the relationship between breakfast skipping and the risk of HF. Specifically, the mediating effects are attributed to the ratio of docosahexaenoic acid (DHA) to total fatty acids (proportion mediated = 9.41%, 95% CI: 2.10-28.61%), glucose (proportion mediated = 6.17%, 95% CI: 0.97-28.53%), and glycoprotein acetyls (GlycA) (proportion mediated = 5.68%, 95% CI: 0.94-21.62%). The combined mediating effects of these three factors total 20.53% (95%CI: 8.59-91.06%). Our research confirms the causal relationship between genetically instrumented breakfast skipping and HF, underscoring the potential mediating roles played by three key blood metabolites: ratio of DHA to total fatty acids, glucose and GlycA. This discovery offers valuable perspectives for clinical strategies targeting HF.

Breakfast consumption, saturated fat intake, and body mass index among medical and non-medical students: a cross-sectional analysis

Changes in dietary patterns and body weight have become a focus of research in undergraduate students. This study compared breakfast consumption, intake of foods high in saturated fat, and BMI between medical and non-medical students. A comparative cross-sectional study was conducted in 4,561 Peruvian university students, of whom 1,464 (32.1%) were from the medical field and 3,097 (67.9%) from the non-medical field. We compared the frequency of breakfast consumption (categorized as regular: 6 to 7 days/week; occasional: 3 to 5 days/week; and rarely or never: 0 to 2 days/week) and the frequency of consumption of foods high in saturated fat. We created simple and multiple linear and Poisson regression models with robust variance to evaluate the association of the mentioned variables with academic fields. Non-medical students (Adjusted Prevalence Ratio [PR] = 0.92, 95% CI 0.86-0.99; p = 0.008) were less likely to eat breakfast regularly compared to medical students. Likewise, consumption of foods high in saturated fats was higher in non-medical students (B = 1.47, 95% CI 0.91-2.04; p < 0.001) compared to medical students. Similarly, the mean BMI of these students was significantly higher than that of medical students (B = 0.33, 95% CI 0.12-0.53; p = 0.002). Although medical students reported relatively healthy eating habits and a lower BMI, there is a widespread need to promote improved diet and lifestyle among the entire university population to reduce the risks of communicable diseases and improve quality of life.

Effects of Early and Late Time-Restricted Feeding on Parameters of Metabolic Health: An Explorative Literature Assessment

Chrono-nutrition (meal timing) aligns food consumption with one's circadian rhythm. The first meal (e.g., breakfast) likely promotes synchronization of peripheral circadian clocks, thereby supporting metabolic health. Time-restricted feeding (TRF) has been shown to reduce body weight (BW) and/or improve cardiovascular biomarkers. In this explorative literature assessment, 13 TRF randomized controlled trials (RCTs) were selected from PubMed and Scopus to evaluate the effects of early (eTRF: first meal before 10:30 a.m.) and late TRF (lTRF: first meal after 11:30 a.m.) on parameters of metabolic health. Although distinct variations in study design were evident between reports, TRF consistently decreased energy intake (EI) and BW, and improved insulin resistance as well as systolic blood pressure. eTRF seemed to have a greater beneficial effect than lTRF on insulin resistance (HOMA-IR). Importantly, most studies did not appear to consider chronotype in their evaluation, which may have underestimated TRF effects. TRF intervention may be a promising approach for risk reduction of human metabolic diseases. To conclusively determine benefits of TRF and identify clear differences between eTRF and lTRF, future studies should be longer-term (≥8 weeks) with well-defined (differences in) feeding windows, include participants chronotypically matching the intervention, and compare outcomes to those of control groups without any dietary limitations.

Does social-norm messaging influence expected satiety and ideal portion-size selection?

A person's perception of how long a food will stave off hunger (expected satiety) and the ideal amount to consume (ideal portion size) are both influenced by food-to-mealtime norms. Here, we examine whether social norms can modulate this effect, in three experimental studies. In study 1 (n = 235) participants were exposed to a social norm suggesting most people enjoyed consuming pasta for breakfast. There was a main effect of food-to-mealtime congruence for expected satiety and ideal portion size (p < 0.001) - participants selected a smaller portion of pasta for breakfast (vs. lunch) - but there were no other main effects/interactions (p ≥ 0.15). Study 2 (n = 200) followed the same approach as study 1, but sought to examine whether the typical volume of food consumed at breakfast and lunch needed to be controlled. Again, there was a main effect of congruence (the same pattern) (p ≤ 0.02) but no other main effects/interactions (p ≥ 0.73). Study 3 (n = 208) followed the same approach as study 2, but the social-norm message was changed to suggest that most people who eat pasta for breakfast found it effectively reduced their hunger. Again, there was a main effect of congruence (the same pattern) (p < 0.001) but no other main effects/interaction (p ≥ 0.26). These studies provide further evidence for the food-to-mealtime effect, but do not provide any evidence that a single, simple social-norm statement can modulate expected satiety or ideal portion size, or interact with the food-to-mealtime effect.

Breakfast skipping and traits of cardiometabolic health: A mendelian randomization study

BACKGROUND

Breakfast skipping has been linked to poor cardiometabolic health in observational studies, but the causality remains unknown. Herein, we used Mendelian randomization (MR) approach to elucidate the potential causal effects of breakfast skipping on cardiometabolic traits.

METHODS

Genetic association estimates for breakfast skipping, cardiometabolic diseases, and cardiometabolic risk factors were extracted from the UK Biobank and several large genome-wide association studies. Two-sample MR analyses were performed primarily using the inverse variance weighted method, followed by sensitivity analysis to test the reliability of results.

RESULTS

MR results indicated no causal relationship between breakfast shipping with coronary heart disease (odds ratio [OR]: 1.079, 95 % confidence interval [CI]: 0.817-1.426; p = 0.591), stroke (OR: 0.877, 95 % CI: 0.680-1.131; p = 0.311), and type 2 diabetes mellitus (OR: 1.114, 95 % CI: 0.631-1.970; p = 0.709). However, genetically predicted breakfast skipping was significantly associated with increased body mass index (β: 0.250, standard error [SE]: 0.079; p = 0.001), waist-to-hip ratio (β: 0.177, SE: 0.076; p = 0.019), and low-density lipoprotein cholesterol (β: 0.260, SE: 0.115; p = 0.024). We found no evidence of association of genetic liability to breakfast skipping with blood pressure, glycemic traits, and other blood lipids. Sensitivity analysis supported the above results.

CONCLUSION

Our study suggested that breakfast skipping is causally linked to weight gain and higher serum low-density lipoprotein cholesterol, which may mediate the increased risk of cardiometabolic diseases reported in epidemiological studies.

Effect of skipping breakfast on cardiovascular risk factors: a grade-assessed systematic review and meta-analysis of randomized controlled trials and prospective cohort studies

Skipping breakfast is one of the most prevalent irregular eating habits. Several pieces of evidence have reported the association between breakfast omission and a higher risk of cardiovascular diseases. Numerous publications have focused on the impact of skipping breakfast on various cardiovascular risk factors. Therefore, the current systematic review and meta-analysis aimed to assess this impact, especially with regard to anthropometric measurements, serum lipid profiles, blood pressure, and glycemic control indicators. A comprehensive search was performed in PubMed, Web of Science, Embase, Scopus, and the Cochrane Central Register of Controlled Trials up to 1 April 2023. A total of 11 eligible trials were identified to evaluate the combined effects of skipping breakfast. Final integrated results demonstrated that breakfast omission significantly decreased the body weight (mean difference = -0.66, 95% CI: -1.09 to -0.24, p = 0.002, I2 = 0.0) and increased the level of serum low-density lipoprotein cholesterol (LDL-C) (mean difference = 9.89, 95% CI: 5.14 to 14.63, p = 0.000, I2 = 17.3). Subgroup analysis also revealed potential factors that may affect the outcomes, for example, the physiological condition of participants, duration, gender, and type of breakfast. In conclusion, skipping breakfast may reduce body weight while increasing the level of serum LDL-C at the same time. In view of the limited trials, further studies are needed to expound the role of breakfast omission in cardiovascular diseases.

Association between frequency of breakfast consumption and cardiometabolic risk in Peruvian university teachers, 2019-2020

Background

Although the relationship between health status and dietary intake has been extensively studied in the general population, there is a lack of research that has specifically examined the association between frequency of breakfast consumption and cardiometabolic risk in university teachers.

Objective

To determine the association between the frequency of breakfast consumption and cardiometabolic risk in university teachers.

Methods

A cross-sectional study was conducted in 176 teachers from a private university located in the eastern region of Lima, Peru (Mage: 37.0 years; SD: 0.8, range: 24-59 years). The study was conducted during the period from December 2019 to February 2020. Information was collected on anthropometric and biochemical parameters and frequency of breakfast consumption. Multinomial logistic regression models were used to explore the association between frequency of breakfast with sociodemographic, anthropometric, and biochemical variables.

Results

The highest prevalence of excess body weight (44.4%) was observed in those who consumed breakfast 0 to 2 days/week, but without statistical differences. Those who reported Low-density lipoprotein cholesterol (LDL-C) < 160 mg/dL were 77% less likely to fall into the 3-5 day/week breakfast frequency category than those who reported a regular frequency of breakfast (6 to 7 days/week) (Adjusted OR = 0.23, 95% CI 0.08 to 0.73; p < 0.05). In addition, teachers who reported a breakfast frequency of 3 to 5 days/week were 83% more likely to have a glucose concentration < 110 mg/dL compared to those who consumed breakfast of 6 to 7 days/week (Adjusted OR = 0.17, 95% CI 0.04 to 0.75; p < 0.05).

Conclusion

Skipping breakfast for an extended period of time can have detrimental effects on cardiometabolic health. Promoting the benefits of breakfast could be a health message of great public health interest.

Breakfast Frequency and Sleep Quality in College Students: The Multiple Mediating Effects of Sleep Chronotypes and Depressive Symptoms

Sleep disorders, which are prominent problems among college students, may be associated with skipping breakfast. Therefore, we aimed to explore the role of sleep chronotypes and depressive symptoms as mediators in the relationship between breakfast frequency and sleep quality. A cross-sectional survey enrolling random samples of 712 college students was conducted by the Questionnaire Star online platform. Statistical description and correlation analysis were performed by SPSS 25.0, and a chain mediation test was performed by model 6 in PROCESS 3.5. The result of the article demonstrated that breakfast frequency can affect sleep quality through two mediating pathways: ① sleep chronotypes, with a mediating effect of 32%; and ② depressive symptoms, with a mediating effect of 52.4%. However, the chain mediating effects of sleep chronotypes and depressive symptoms was not significant, and neither was the direct effect of breakfast frequency on sleep quality. Breakfast frequency can indirectly affect sleep quality by adjusting sleep chronotypes and depressive symptoms. Regular breakfast can increase morning and intermediate sleep chronotypes, reduce depressive symptoms, and thus improve sleep quality.

Fasting Before Evening Exercise Reduces Net Energy Intake and Increases Fat Oxidation, but Impairs Performance in Healthy Males and Females

Acute morning fasted exercise may create a greater negative 24-hr energy balance than the same exercise performed after a meal, but research exploring fasted evening exercise is limited. This study assessed the effects of 7-hr fasting before evening exercise on energy intake, metabolism, and performance. Sixteen healthy males and females (n = 8 each) completed two randomized, counterbalanced trials. Participants consumed a standardized breakfast (08:30) and lunch (11:30). Two hours before exercise (16:30), participants consumed a meal (543 ± 86 kcal; FED) or remained fasted (FAST). Exercise involved 30-min cycling (∼60% VO2peak) and a 15-min performance test (∼85% VO2peak; 18:30). Ad libitum energy intake was assessed 15 min postexercise. Subjective appetite was measured throughout. Energy intake was 99 ± 162 kcal greater postexercise (p < .05), but 443 ± 128 kcal lower over the day (p < .001) in FAST. Appetite was elevated between the preexercise meal and ad libitum meal in FAST (p < .001), with no further differences (p ≥ .458). Fat oxidation was greater (+3.25 ± 1.99 g), and carbohydrate oxidation was lower (-9.16 ± 5.80 g) during exercise in FAST (p < .001). Exercise performance was 3.8% lower in FAST (153 ± 57 kJ vs. 159 ± 58 kJ, p < .05), with preexercise motivation, energy, readiness, and postexercise enjoyment also lower in FAST (p < .01). Fasted evening exercise reduced net energy intake and increased fat oxidation compared to exercise performed 2 hr after a meal. However, fasting also reduced voluntary performance, motivation, and exercise enjoyment. Future studies are needed to examine the long-term effects of this intervention as a weight management strategy.

Timing of daily calorie loading affects appetite and hunger responses without changes in energy metabolism in healthy subjects with obesity

Morning loaded calorie intake in humans has been advocated as a dietary strategy to improve weight loss. This is also supported by animal studies suggesting time of eating can prevent weight gain. However, the underlying mechanisms through which timing of eating could promote weight loss in humans are unclear. In a randomized crossover trial (NCT03305237), 30 subjects with obesity/overweight underwent two 4-week calorie-restricted but isoenergetic weight loss diets, with morning loaded or evening loaded calories (45%:35%:20% versus 20%:35%:45% calories at breakfast, lunch, and dinner, respectively). We demonstrate no differences in total daily energy expenditure or resting metabolic rate related to the timing of calorie distribution, and no difference in weight loss. Participants consuming the morning loaded diet reported significantly lower hunger. Thus, morning loaded intake (big breakfast) may assist with compliance to weight loss regime through a greater suppression of appetite.

Association between Breakfast Meal Categories and Timing of Physical Activity of Japanese Workers

Background: Breakfast is the most important meal of the day and has been associated with longevity. Regular breakfast consumers often have a healthy lifestyle, including a healthy diet and regular physical activity. Methods: We examined the association between breakfast type, chronotype (morningness-eveningness), and physical activity in 3395 Japanese workers using a cross-sectional web survey. Results: Participants who ate Japanese breakfasts showed an early chronotype, while those who ate breakfast cereal exhibited a later chronotype. Physical activity was positively associated with adopting a Japanese breakfast style. Japanese breakfast eaters performed physical activities from 6:00–9:00 compared with other breakfast eaters. Conclusion: Our findings suggest that eating a Japanese breakfast is associated with an earlier chronotype (morningness) and higher physical activity.

Portions selected to stave off hunger are reduced when food is presented in an 'unusual' food-to-mealtime context: An implication for implicit satiety drivers

Research suggests that the role of expected satiety in influencing portion-size selection is reduced when food is presented in unusual food-to-mealtime contexts; however, the underlying mechanism has not been explored. Other research has revealed that different implicit satiety drivers (e.g., to stop momentary hunger or obtain complete fullness) are associated with different perceived levels of stomach fullness, portion-size selections and can change on instruction. The current study explored whether changes in expected satiety and ideal portions in congruous vs incongruous contexts can be explained by changes in implicit satiety drivers. Another aim was to investigate a previous exploratory finding suggesting that portions selected to stave off hunger are reduced when foods are presented in unusual food-to-mealtime contexts. At two trials (breakfast/lunch), participants (n = 40) selected a portion of typical lunch (pasta) and breakfast (porridge) foods via a psychophysical computer-based method 1) to stave off hunger for 5 h, and 2) as an ideal portion. Participants also indicated their perceived level of stomach fullness associated with 1) each portion, and 2) five implicit satiety drivers. Results revealed that a smaller average portion was selected to stave off hunger in incongruous (vs congruous) food-to-mealtime contexts (531 ± 229 vs 575 ± 236 kcal) (p = 0.008). This suggests that expected satiety is influenced by momentary context; foods are perceived to be more satiating when consumed in unusual (vs usual) contexts. Results also showed that implicit satiety drivers are malleable in regard to the portion size associated with a perceived level of stomach fullness and that this can vary contextually. These findings provide initial evidence to explain the psychological mechanism underlying the contextual differences observed in portion-size selections. Future work should explore longer-term impacts of consuming foods in unusual contexts.

Supplementation of Protein at Breakfast Rather Than at Dinner and Lunch Is Effective on Skeletal Muscle Mass in Older Adults

Background: The effects of different intake patterns of meal protein on muscle mass have not been clarified. We cross-sectionally and longitudinally examined the effect of different timing of protein intake on sarcopenia-related factors in older adults.

Methods: This cross-sectional study 1 included 219 (male, n = 69, female, n = 150) elderly subjects aged ≥65 years. Subjects who consumed more protein at breakfast than at dinner were grouped into the morning group (MG, n = 76; male, n = 26; female, n = 50), and those who consumed more protein at dinner than at breakfast were grouped into the evening group (EG, n = 143; male, n = 43; female, n = 100). In cross-sectional study 2-1 (female, n = 125), the subjects were classified into four groups according to the number of meals with sufficient protein intake. In cross-sectional studies 2-2 (female, n = 125) and 2-3 (female, n = 27), the subjects were classified into eight groups and three groups according to whether they had consumed sufficient protein at three meals; sarcopenia-related factors were compared. The intervention study was a placebo-controlled, double-blind, randomized controlled trial that included 40 elderly women with low daily breakfast protein intake. The subjects were divided into four groups: morning protein and placebo intake groups and evening protein and placebo intake groups. Each group consumed the test food (containing 10 g milk protein) or placebo in the morning or evening for 12 weeks. Blood indices and physical function were assessed before and after the intervention.

Results: Comparing all subjects, MG showed significantly higher handgrip strength than did EG (P < 0.05). The higher ratio of morning protein intake relative to the total protein intake, the better the muscle mass (r = 0.452, P < 0.05) and handgrip strength (r = 0.383, P < 0.05). The intervention study showed an increase in muscle mass with the intake of milk protein in the morning rather than in the evening (P < 0.05).

Conclusions: Protein intake at breakfast might have relatively stronger effects on skeletal muscle mass than at lunch and dinner.

Effect of the perception of breakfast consumption on subsequent appetite and energy intake in healthy males

Purpose

This study aimed to assess the effects of consuming a very-low-energy placebo breakfast on subsequent appetite and lunch energy intake.

Methods

Fourteen healthy males consumed water-only (WAT), very-low-energy, viscous placebo (containing water, low-calorie flavoured squash, and xanthan gum; ~ 16 kcal; PLA), and whole-food (~ 573 kcal; FOOD) breakfasts in a randomised order. Subjects were blinded to the energy content of PLA and specific study aims. Venous blood samples were collected pre-breakfast, 60- and 180-min post-breakfast to assess plasma acylated ghrelin and peptide tyrosine tyrosine concentrations. Subjective appetite was measured regularly, and energy intake was assessed at an ad libitum lunch meal 195-min post-breakfast.

Results

Lunch energy intake was lower during FOOD compared to WAT (P < 0.05), with no further differences between trials (P ≥ 0.132). Cumulative energy intake (breakfast plus lunch) was lower during PLA (1078 ± 274 kcal) and WAT (1093 ± 249 kcal), compared to FOOD (1554 ± 301 kcal; P < 0.001). Total area under the curve (AUC) for hunger, desire to eat and prospective food consumption were lower, and fullness was greater during PLA and FOOD compared to WAT (P < 0.05). AUC for hunger was lower during FOOD compared to PLA (P < 0.05). During FOOD, acylated ghrelin was suppressed compared to PLA and WAT at 60 min (P < 0.05), with no other hormonal differences between trials (P ≥ 0.071).

Conclusion

Consuming a very-low-energy placebo breakfast does not alter energy intake at lunch but may reduce cumulative energy intake across breakfast and lunch and attenuate elevations in subjective appetite associated with breakfast omission.

Trial registration

NCT04735783, 2nd February 2021, retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02727-5.

Breakfast Location Effect on Breakfast Quality and Obesity Risk in Saudi Female College Students

Background:

There is a lack of data regarding breakfast consumption and quality among college students in the Kingdom of Saudi Arabia.

Objective:

The objective of this study was to assess the prevalence of breakfast consumption and examine the effect of breakfast location on breakfast nutritional quality and obesity risk among female college students at Taibah University.

Methods:

A total of 658 students participated in this cross-sectional study. Based on the Child and Adult Care Food Program (CACFP) recommendations, breakfast quality scores were computed by summing the individual food components and categorizing participants according to tertiles of the breakfast score distribution. Mixed-effects repeatedmeasures models were used to examine BMI categories with increasing tertiles of breakfast quality scores, stratified by breakfast location.

Results and Discussion:

Approximately 68% of the participants reported having breakfast regularly. The mean breakfast quality score was determined for students who had breakfast at home (12.5 ± 0.11), at college (10.41± 0.06), and in other places (8.19± 0.48). Obesity was associated with lower average breakfast quality scores based on breakfast location [mean quintile 3 compared with 1 difference: home 13.6 (P < 0.001), college 9.1 (P < 0.001), other 8.6 (P < 0.001)].

Conclusion:

The findings presented here indicated that a high percentage of students consume breakfast regularly. Students who had breakfast at home had high scores, which indicated good breakfast quality and a decreased risk of obesity. Further research on breakfast quality is needed in this area, as it affects the nutritional status and quality of life of the younger population.

Omission of a carbohydrate-rich breakfast impairs evening endurance exercise performance despite complete dietary compensation at lunch

Omission of a carbohydrate-rich breakfast followed by consuming an ad libitum lunch impairs evening exercise performance. However, it is unclear if this is due to breakfast omission per se, or secondary to lower carbohydrate intake over the day. To test whether impaired evening performance following breakfast omission persists when complete dietary compensation occurs at lunch, in a randomised cross-over design, eleven highly trained cyclists (age: 25 ± 7 y, VO₂max: 61 ± 5 ml·kg^-1·min^-1) completed two trials: breakfast (B) and no breakfast (NB). During B, participants consumed an individualised breakfast (583 ± 54 kcal; 8-9am) and lunch (874 ± 80 kcal; 12-2pm), whilst during NB participants fasted until 12pm and then consumed a standardised lunch (1457 ± 134 kcal: 12-2pm). The overall energy (1457 ± 134 kcal) and macronutrient profile (carbohydrate: 81.5 ± 0.4%, fat: 5.8 ± 0.1%, protein: 12.7 ± 0.3%) was identical in both trials, with timing the only difference. Mean power output during a 20 km time trial performed in the evening was ~3% lower in NB compared to B (mean difference [95% CI]: -9.1 [-15.3, -2.9] watts, p < 0.01 for condition main effect). No differences in heart rate, blood glucose or blood lactate concentrations were apparent, but perception of effort appeared to be higher in the early stages of the time trial in NB compared to B despite lower power output. Impaired high-intensity endurance performance in the evening following breakfast omission is related to meal timing rather than carbohydrate intake / availability. Provision of an early morning high-carbohydrate meal should be considered to optimise evening exercise performance.

Nutrient Timing: A Garage Door of Opportunity?

Nutrient timing involves manipulation of nutrient consumption at specific times in and around exercise bouts in an effort to improve performance, recovery, and adaptation. Its historical perspective centered on ingestion during exercise and grew to include pre- and post-training periods. As research continued, translational focus remained primarily on the impact and outcomes related to nutrient consumption during one specific time period to the exclusion of all others. Additionally, there seemed to be increasing emphasis on outcomes related to hypertrophy and strength at the expense of other potentially more impactful performance measures. As consumption of nutrients does not occur at only one time point in the day, the effect and impact of energy and macronutrient availability becomes an important consideration in determining timing of additional nutrients in and around training and competition. This further complicates the confining of the definition of “nutrient timing” to one very specific moment in time at the exclusion of all other time points. As such, this review suggests a new perspective built on evidence of the interconnectedness of nutrient impact and provides a pragmatic approach to help frame nutrient timing more inclusively. Using this approach, it is argued that the concept of nutrient timing is constrained by reliance on interpretation of an “anabolic window” and may be better viewed as a “garage door of opportunity” to positively impact performance, recovery, and athlete availability.

Breakfast Skipping, Body Composition, and Cardiometabolic Risk: A Systematic Review and Meta-Analysis of Randomized Trials

OBJECTIVE

The objective of this study was to evaluate the effect of skipping breakfast on body composition and cardiometabolic risk factors.

METHODS

This study conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating breakfast skipping compared with breakfast consumption. Inclusion criteria included age ≥ 18, intervention duration ≥ 4 weeks, ≥ 7 participants per group, and ≥ 1 body composition measure. Random-effects meta-analyses of the effect of breakfast skipping on body composition and cardiometabolic risk factors were performed.

RESULTS

Seven RCTs (n = 425 participants) with an average duration of 8.6 weeks were included. Compared with breakfast consumption, breakfast skipping significantly reduced body weight (weighted mean difference [WMD] = -0.54 kg [95% CI: -1.05 to -0.03], P = 0.04, I²  = 21.4%). Percent body fat was reported in 5 studies and was not significantly different between breakfast skippers and consumers. Three studies reported on low-density lipoprotein cholesterol (LDL), which was increased in breakfast skippers as compared with breakfast consumers (WMD = 9.24 mg/dL [95% CI: 2.18 to 16.30], P = 0.01). Breakfast skipping did not lead to significant differences in blood pressure, total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, C-reactive protein, insulin, fasting glucose, leptin, homeostatic model assessment of insulin resistance, or ghrelin.

CONCLUSIONS

Breakfast skipping may have a modest impact on weight loss and may increase LDL in the short term. Further studies are needed to provide additional insight into the effects of breakfast skipping.

Appetite and energy intake responses to breakfast consumption and carbohydrate supplementation in hypoxia

PURPOSE

The purpose of experiment one was to determine the appetite, acylated ghrelin and energy intake response to breakfast consumption and omission in hypoxia and normoxia. Experiment two aimed to determine the appetite, acylated ghrelin and energy intake response to carbohydrate supplementation after both breakfast consumption and omission in hypoxia.

METHODS

In experiment one, twelve participants rested and exercised once after breakfast consumption and once after omission in normobaric hypoxia (4300 m: F_iO₂ ~11.7%) and normoxia. In experiment two, eleven participants rested and exercised in normobaric hypoxia (4300 m: F_iO₂ ~11.7%), twice after consuming a high carbohydrate breakfast and twice after breakfast omission. Participants consumed both a carbohydrate (1.2g·min^-1 glucose) and a placebo beverage after breakfast consumption and omission. Measures of appetite perceptions and acylated ghrelin were taken at regular intervals throughout both experiments and an ad-libitum meal was provided post-exercise to quantify energy intake.

RESULTS

Breakfast consumption had no significant effect on post exercise energy intake or acylated ghrelin concentrations, despite reductions in appetite perceptions. As such, breakfast consumption increased total trial energy intake compared with breakfast omission in hypoxia (7136 ± 2047 kJ vs. 5412 ± 1652 kJ; p = 0.02) and normoxia (9276 ± 3058 vs. 6654 ± 2091 kJ; p < 0.01). Carbohydrate supplementation had no effect on appetite perceptions or acylated ghrelin concentrations after breakfast consumption or omission. As such, carbohydrate supplementation increased total energy intake after breakfast consumption (10222 ± 2831 kJ vs. 7695 ± 1970 kJ p < 0.01) and omission (8058 ± 2574 kJ vs. 6174 ± 2222 kJ p = 0.02).

CONCLUSION

Both breakfast consumption and carbohydrate supplementation provide beneficial dietary interventions for increasing energy intake in hypoxic conditions.

Viscous placebo and carbohydrate breakfasts similarly decrease appetite and increase resistance exercise performance compared with a control breakfast in trained males

Given the common view that pre-exercise nutrition/breakfast is important for performance, the present study investigated whether breakfast influences resistance exercise performance via a physiological or psychological effect. Twenty-two resistance-trained, breakfast-consuming men completed three experimental trials, consuming water-only (WAT), or semi-solid breakfasts containing 0 g/kg (PLA) or 1·5 g/kg (CHO) maltodextrin. PLA and CHO meals contained xanthan gum and low-energy flavouring (approximately 122 kJ), and subjects were told both 'contained energy'. At 2 h post-meal, subjects completed four sets of back squat and bench press to failure at 90 % ten repetition maximum. Blood samples were taken pre-meal, 45 min and 105 min post-meal to measure serum/plasma glucose, insulin, ghrelin, glucagon-like peptide-1 and peptide tyrosine-tyrosine concentrations. Subjective hunger/fullness was also measured. Total back squat repetitions were greater in CHO (44 (sd 10) repetitions) and PLA (43 (sd 10) repetitions) than WAT (38 (sd 10) repetitions; P < 0·001). Total bench press repetitions were similar between trials (WAT 37 (sd 7) repetitions; CHO 39 (sd 7) repetitions; PLA 38 (sd 7) repetitions; P = 0·130). Performance was similar between CHO and PLA trials. Hunger was suppressed and fullness increased similarly in PLA and CHO, relative to WAT (P < 0·001). During CHO, plasma glucose was elevated at 45 min (P < 0·05), whilst serum insulin was elevated (P < 0·05) and plasma ghrelin suppressed at 45 and 105 min (P < 0·05). These results suggest that breakfast/pre-exercise nutrition enhances resistance exercise performance via a psychological effect, although a potential mediating role of hunger cannot be discounted.

Evaluation of the Nutritional Quality of Breakfast Cereals Sold on the Italian Market: The Food Labelling of Italian Products (FLIP) Study

Breakfast cereals are present on the market as different types and, in general, are one of the food categories in which voluntary information, such as nutrition or health claims (NHC) or gluten free (GF) declarations, have the largest distribution. The aims of the present study were to compare (i) the nutritional declaration among different types of breakfast cereals, as well as among products with and without NHC or GF declarations; and (ii) the salt and sugar contents with the “Italian shared objectives for the improvement of the nutritional characteristics of food”. To this aim, the nutrition declarations of 371 different breakfast cereal items, available in 13 retailers present on the Italian market, were analysed. Data showed an elevated inter-product variability, with cereal bars and muesli having the highest energy, total fat, and saturate contents per 100 g. Limited differences were found comparing products with and without NHC, as well as those with GF declaration. Most of the breakfast cereals were compliant to the shared objectives, although some items with NHC or GF declaration still have sugar or salt contents higher than these objectives. In conclusion, these data suggest that the different characteristics and the regulated information reported on the food label should not be considered as a marker of the overall nutritional quality. Thus, this study supports the importance of reading and understanding the information made on food label.

Breakfast Nutritional Quality and Cognitive Interference in University Students from Mexico City

Skipping breakfast might have an impact on cognitive functions, such as interference, which is a basic capacity of executive functions that denotes the possibility of controlling an automated response. This study aimed to analyze the association between nutritional quality of breakfast and cognitive interference in a sample of university students. A cross-sectional study was conducted, a total of 422 students between 18 and 25 years participated. Cognitive interference was assessed with the Stroop Test. Breakfast was assessed with a questionnaire assigning a score for each serving of each food group that was consumed. Logistic regression models were performed. The performance in cognitive tasks was slower in those who had a poor breakfast (32.9 ± 6 vs 29.3 ± 6 s, p < 0.050). Poor cognitive interference was greater in students with poor breakfast (53% versus 23%, p = 0.001). A slower word reading was associated with skipping vegetables (OR: 2.78, 95% CI: 0.09-2.13), and cereals (OR: 1.70, 95% CI: 1.03-2.81). Wrong color identification was associated with skipping fruits (OR: 1.55, 95% CI: 1.43-1.99) and animal protein sources (OR: 1.63, 95% CI: 1.07-2.49). Skipping fat-rich cereals was a protector factor (OR: 0.55, 95% CI: 0.36-0.85). Difficulty in the ability to inhibit interference was associated with skipping vegetables (OR: 2.72, 95% CI: 1.25-4.80) and cereals (OR: 2.65, 95% CI: 1.28-4.68). The nutritional quality of breakfast was associated with the time spent answering the Stroop test, but not with cognitive interference.

Skipping Breakfast and a Meal at School: Its Correlates in Adiposity Context. Report from the ABC of Healthy Eating Study of Polish Teenagers

Little is known on skipping breakfast and a meal at school, especially considered together. The study identified nutrition knowledge-related, lifestyle (including diet quality, physical activity, and screen time) and socioeconomic correlates of skipping breakfast and a meal at school, considered together or alone and assessed the association of skipping these meals with adiposity markers in Polish teenagers. The sample consisted of 1566 fourth and fifth grade elementary school students (11–13 years). The study was designed as a cross-sectional study. Data related to the consumption of selected food items and meals, physical activity, screen time, sociodemographic factors, and nutrition knowledge (all self-reported) were collected (in 2015–2016) with a short form of a food frequency questionnaire. Respondents reported the usual consumption of breakfast (number of days/week) and a meal or any food eaten at school (number of school days/week) labelled as ‘a meal at school’. The measurements of body weight, height, and waist circumference were taken. BMI-for-age ≥25 kg/m² was considered as a marker of overweight/obesity (general adiposity), while waist-to-height ratio ≥0.5 as a marker of central obesity (central adiposity). A multivariate logistic regression was applied to verify the association between variables. A total of 17.4% of teenagers frequently skipped breakfast (4–7 days/week), 12.9% frequently skipped a meal at school (3–5 school days/week), while 43.6% skipped both of these meals a few times a week. Predictors of skipping breakfast and/or a meal at school were female gender, age over 12 years, urban residence, lower family affluence, lower nutrition knowledge, higher screen time, and lower physical activity. In comparison to “never-skippers,” “frequent breakfast skippers” were more likely to be overweight/obese (odds ratio, OR 1.89; 95% confidence interval, 95%CI 1.38, 2.58) and centrally obese (OR 1.63; 95%CI 1.09, 2.44), while skippers a few times a week of both of these meals were more likely to be overweight/obese (OR 1.37; 95%CI 1.06, 1.78). Concluding, we estimated that a large percentage of Polish teenagers (approx. 44%) usually skipped both breakfast and a meal at school a few times a week. Similar predictors of skipping breakfast and predictors of skipping a meal at school were identified. Special attention should be paid to promoting shortening screen time and increasing physical activity and teenagers’ nutrition knowledge which are relatively easily modifiable correlates. The study shows that skipping both of these meals a few times a week was associated with general adiposity and also strengthens previous evidence showing the association of frequent skipping breakfast with general and central adiposity.

Association between eating behavior and poor glycemic control in Japanese adults

This study investigated the relationship between eating behavior and poor glycemic control in 5,479 Japanese adults with hemoglobin A1c (HbA1c) <6.5% who participated in health checks. Respondents to a 2013 baseline survey of eating behavior, including skipping breakfast and how quickly they consumed food were followed up until 2017. We defined poor glycemic control after follow-up as HbA1c ≥6.5%, or increases in HbA1c of ≥0.5% and/or being under medication to control diabetes. We identified 109 (2.0%) respondents who met these criteria for poor glycemic control. After adjusting for sex, age, smoking status, body mass index (BMI), and eating behavior, the risk of poor glycemic control was increased in males (odds ratio [OR], 2.38; 95% confidence interval [CI] 1.37–4.12; p < 0.01), and associated with being older (OR, 1.07; 95% CI, 1.04–1.11; p < 0.001), having a higher BMI (OR, 1.29; 95% CI 1.23–1.35; p < 0.001), skipping breakfast ≥3 times/week (OR, 2.44; 95% CI, 1.35–4.41; p < 0.01), and changing from eating slowly or at medium speed to eating quickly (OR, 2.11; 95% CI, 1.04–4.26; p < 0.05). In conclusion, Japanese adults who were male, older, had a high BMI, skipped breakfast ≥3 times/week and ate quickly were at increased risk for poor glycemic control.

Household food insecurity and breakfast skipping: Their association with depressive symptoms

Household food insecurity limits families' access to sufficient and varied safe foods, which may result in problems such as insufficient food intake and nutritional imbalance. This may lead to health issues such as obesity, chronic illness, mental health problems, and even poor quality of life. Breakfast skipping is a risk factor for eating disorders which is related to diseases such as metabolic disorder and depressive symptoms. This study examined household food insecurity and breakfast skipping and their association with depressive symptoms. In this study, we used data from the 2015 Korean Community Health Survey. Study participants were a total of 225,965 people aged 18 years or older who answered questions related to eating habits. Multiple logistic regression analyses were used to identify factors associated with depressive symptoms. Those in households with low food security and very low food security were more likely to experience depressive symptoms. Individuals that skip breakfast 2 days or more per week were more likely to experience depressive symptoms. Our study suggests that those living in households with lower food security and who skip breakfast often should pay more attention to their mental health.

Satiating Effect of High Protein Diets on Resistance-Trained Subjects in Energy Deficit

Short-term energy deficit strategies are practiced by weight class and physique athletes, often involving high protein intakes to maximize satiety and maintain lean mass despite a paucity of research. This study compared the satiating effect of two protein diets on resistance-trained individuals during short-term energy deficit. Following ethical approval, 16 participants (age: 28 ± 2 years; height: 1.72 ± 0.03 m; body-mass: 88.83 ± 5.54 kg; body-fat: 21.85 ± 1.82%) were randomly assigned to 7-days moderate (PRO_MOD: 1.8 g·kg^-1·d^-1) or high protein (PRO_HIGH: 2.9 g·kg^-1·d^-1) matched calorie-deficit diets in a cross-over design. Daily satiety responses were recorded throughout interventions. Pre-post diet, plasma ghrelin and peptide tyrosine tyrosine (PYY), and satiety ratings were assessed in response to a protein-rich meal. Only perceived satisfaction was significantly greater following PRO_HIGH (67.29 ± 4.28 v 58.96 ± 4.51 mm, p = 0.04). Perceived cravings increased following PRO_MOD only (46.25 ± 4.96 to 57.60 ± 4.41 mm, p = 0.01). Absolute ghrelin concentration significantly reduced post-meal following PRO_MOD (972.8 ± 130.4 to 613.6 ± 114.3 pg·mL^-1; p = 0.003), remaining lower than PRO_HIGH at 2 h (-0.40 ± 0.06 v -0.26 ± 0.06 pg·mL^-1 normalized relative change; p = 0.015). Absolute PYY concentration increased to a similar extent post-meal (PRO_MOD: 84.9 ± 8.9 to 147.1 ± 11.9 pg·mL^-1, PRO_HIGH: 100.6 ± 9.5 to 143.3 ± 12.0 pg·mL^-1; p < 0.001), but expressed as relative change difference was significantly greater for PRO_MOD at 2 h (+0.39 ± 0.20 pg·mL^-1 v -0.28 ± 0.12 pg·mL^-1; p = 0.001). Perceived hunger, fullness and satisfaction post-meal were comparable between diets (p > 0.05). However, desire to eat remained significantly blunted for PRO_MOD (p = 0.048). PRO_HIGH does not confer additional satiating benefits in resistance-trained individuals during short-term energy deficit. Ghrelin and PYY responses to a test-meal support the contention that satiety was maintained following PRO_MOD, although athletes experiencing negative symptoms (i.e., cravings) may benefit from protein-rich meals as opposed to over-consumption of protein.

Omission of carbohydrate-rich breakfast impairs evening 2000-m rowing time trial performance

PURPOSE

The effect of breakfast omission on evening high-intensity exercise performance has not previously been studied.

METHODS

In a randomised and counterbalanced cross-over design, 10 competitive rowers (2 male, 8 female; mean ± SD: age 21 ± 2 y, height 176 ± 7 cm, weight 76 ± 12 kg, body fat 19.7 ± 6.8%) completed two trials (individualised carbohydrate-rich breakfast (BT; 831 ± 67 kcal eaten before 09:00) and no-breakfast (NBT; extended overnight fast until 12:00)). Following ad libitum afternoon food intake, participants completed a 2000-m time-trial on a rowing ergometer between 16:30 and 18:00. Appetite and energy intake were measured throughout the day, whilst power output, time, heart rate, blood lactate, blood glucose and RPE were assessed during the time trial.

RESULTS

Appetite ratings were higher throughout the morning in NBT compared with BT, but there were no differences in ratings in the afternoon. Energy intake at lunch was greater NBT compared with BT (1236 ± 594 vs 836 ± 303 kcal, p < .05), which partly compensated for breakfast omission, although overall energy intake tended to be lower in NBT compared with BT (1236 ± 594 vs 1589 ± 225 kcal, p = .08). The time taken to complete the 2000-m time trial was greater in NBT compared with BT (469.2 ± 43.4 vs 465.7 ± 43.3 s; p < .05). No differences in heart rate, blood glucose and blood lactate responses were apparent, but overall RPE was higher in NBT compared with BT (17.8 ± 0.9 vs 16.7 ± 0.7 au, p < .05).

CONCLUSION

The omission of a carbohydrate-rich breakfast impaired evening performance during a 2000-m rowing time trial. This finding has implications for optimising evening high-intensity exercise performance.

Nature and Cognitive Perception of 4 Different Breakfast Meals Influence Satiety-Related Sensations and Postprandial Metabolic Responses but Have Little Effect on Food Choices and Intake Later in the Day in a Randomized Crossover Trial in Healthy Men

Background

Regular breakfast consumption is associated with better health status and healthier food intake throughout the day, but this association is a complex interaction of several factors.

Objective

This study aimed to investigate the effect of nutritional and cognitive-perceived characteristics of breakfast on metabolic and behavioral variables related to food intake.

Methods

The study was a randomized, crossover, controlled trial, with 4 experimental conditions consisting of 3 iso-energetic breakfasts and 1 energy-free control meal. Breakfasts had similar nutritional profiles but differed for glycemic index (GI), glycemic load (GL), and perceived healthiness, satiety, palatability, or energy content. Fifteen healthy normal-weight men [means ± SDs; age: 24 ± 2 y; body mass index (BMI; kg/m2) 23.4 ± 1.6] underwent each experimental condition in random order during 4 different weeks, separated by ≥1-wk washout. On the third day of each intervention week, postprandial blood variables (with insulin as primary outcome), satiety ratings, and food intake during an ad libitum lunch consumed 4 h after breakfast (secondary outcomes) were measured for each experimental condition.

Results

A main effect of time, treatment, and time × treatment was found for postprandial insulin, glucose, and nonesterified fatty acids (P < 0.001 for all) after having the 3 iso-energetic breakfasts or the energy-free control one. Postprandial satiety was similar for the 3 energy-containing breakfasts, but higher when compared with the energy-free control (P < 0.001). No difference in energy intake was observed for the ad libitum lunch, whereas prolonged breakfast skipping was compensated by an increase (around +10%) in the average energy intake during the rest of the day, resulting in no differences in the total daily energy intake among the 4 conditions.

Conclusions

Although other advantages might exist for breakfasts based on low-GI/low-GL foods, our findings support the hypothesis that minor differences in nutritional and perceived characteristics of breakfast are of limited importance regarding medium-term energy intake in healthy men. This trial was registered at clinicaltrials.gov as BRNN-014 NCT02516956.

Food perception at lunchtime does not depend on the nutritional and perceived characteristics of breakfast

Breakfast consumption can entail nutritional advantages positively affecting food choices. This study investigated the effect of minor changes in breakfast composition on the perceived attributes of foods, both at breakfast and at lunchtime. Four breakfasts were defined considering nutritional and perceptual factors. Three breakfasts varied just for a single cereal-based chocolate-containing food item, while a control breakfast mimicked fasting conditions. Breakfast perception was assessed before and after consumption. Subjects rated breakfast energy content on the basis of single items, while judged breakfast healthiness as a whole, suggesting that the combination of different ingredients can modify the perceived health value of foods. Additionally, 4 h after breakfast, a perceptual evaluation of lunch-related food images was performed, without differences among breakfasts. This study extends current knowledge on the relationship between subjective perceptual attributes and objective energy value and food composition, as well as on breakfast impact on food perception at lunchtime.

Breakfast Macronutrient Composition Influences Thermic Effect of Feeding and Fat Oxidation in Young Women Who Habitually Skip Breakfast

The purpose of this study was to determine if breakfast macronutrient composition improved thermic effect of feeding (TEF) and appetite after a one-week adaptation in young women who habitually skip breakfast. A randomized, controlled study was conducted in females (24.1 ± 2 years), who skip breakfast (≥5 times/week). Participants were placed into one of three groups for eight days (n = 8 per group): breakfast skipping (SKP; no breakfast), carbohydrate (CHO; 351 kcal; 59 g CHO, 10 g PRO, 8 g fat) or protein (PRO; 350 kcal; 39 g CHO, 30 g PRO, 8 g fat). On days 1 (D1) and 8 (D8), TEF, substrate oxidation, appetite and blood glucose were measured. PRO had higher (p < 0.05) TEF compared to SKP and CHO on D1 and D8, with PRO having 29% higher TEF than CHO on D8. On D1, PRO had 30.6% higher fat oxidation than CHO and on D8, PRO had 40.6% higher fat oxidation than CHO. SKP had higher (p < 0.05) fat oxidation on D1 and D8 compared to PRO and CHO. There was an interaction (p < 0.0001) of time and breakfast on appetite response. In addition, CHO had a significant increase (p < 0.05) in PP hunger response on D8 vs. D1. CHO and PRO had similar PP (postprandial) glucose responses on D1 and D8. Consumption of PRO breakfast for 8 days increased TEF compared to CHO and SKP, while consumption of CHO for one week increased PP hunger response.