Why Teens Skip Breakfast: What a Spanish Study Shows About the Mediterranean Diet and Its Risks

Teenagers are increasingly leaving home without breakfast - and this is not a random detail, but a marker of a larger picture of diet and lifestyle. A new study in the journal Nutrients examined the relationship between breakfast skipping, adherence to the Mediterranean diet and other factors in schoolchildren in Spain.

Every third schoolgirl/boy “misses” breakfast at least once during the school week; this happens more often among girls. Skipping goes hand in hand with low adherence to the Mediterranean diet, excess weight, short sleep and excessive screen time.

Background of the study

Adolescent breakfast skipping is a persistent behavioral trend in recent years. Although breakfast is traditionally viewed as the “most important meal of the day” for energy and cognitive performance, the proportion of adolescents who skip it is increasing. Observational data link it to adverse outcomes: overweight and obesity, unfavorable lipid profiles, high blood pressure, and lower academic performance. However, prevalence estimates vary widely due to different definitions of “skipping,” from 1.3% to 74.7% (mean ~16%). These discrepancies highlight the importance of precise operational criteria when studying the phenomenon.

There are several possible explanations. First, skipping breakfast may lead to compensatory overeating later in the day. Second, “breakfast-skipping” adolescents have, on average, lower diet quality: fewer fruits, vegetables, and high-nutrient density foods. Physiological mechanisms include shifts in appetite hormones (increased ghrelin and decreased leptin due to prolonged nighttime and morning hunger), decreased insulin sensitivity, and changes in the circadian rhythm of cortisol, all of which may impair hunger control and metabolic regulation.

The connection with the Mediterranean diet is of particular importance. Regular breakfasts are associated with higher adherence to the Mediterranean diet, while low levels are more common among those who skip breakfast. In Spain, according to HBSC, approximately one in five teenagers skips breakfast on weekdays, with girls doing so more often than boys - therefore, a gender-separated analysis of risk factors is considered methodologically justified.

Finally, behavioural and environmental factors are important: short sleep duration, long screen time, and lack of moderate-intensity physical activity increase the likelihood of morning skipping. Family and school influences are also significant: educational programmes, availability of school breakfast, parental dietary habits, and socioeconomic context can both strengthen and moderate these associations. These multilayered determinants are the focus of this study.

What is the study about?

• Where and who: 547 teenagers aged 14-15 from urban and rural schools in the autonomous region of Castilla-La Mancha (Spain).
• Design: Cross-sectional study with anonymous questionnaires on school days.
• What was measured:
  • daily breakfast/skips,
  • adherence to the Mediterranean diet according to the KIDMED scale,
  • sleep habits and screen time,
  • body weight (categories: normal/overweight/obese),
  • well-being according to EuroQol domains (including anxiety/sadness, pain/discomfort).

Key figures

• 33.5% of teenagers skipped breakfast at least once during the school week.
• Girls vs. boys: 43.3% vs. 24.4% (p<0.001). Daily absences: 14.2% for girls and 6.9% for boys.
• Model quality: Sex-specific logistic regression models showed good discriminatory power (AUC ~0.80 in both sexes).

What goes along with skipping breakfast

• Low adherence to the Mediterranean diet (KIDMED total score).
• Short nap.
• Long screen time (especially >4 hours/day for boys).
• Overweight/obesity.
• In girls, low olive oil consumption was additionally noted as a characteristic feature of the risk profile.
• In boys, there is a link with the consumption of industrial baked goods (the direction of the effect in the model requires careful interpretation, see primary tables).

Why is this important?

• Skipping breakfast isn't just about "hunger before the big break." It correlates with overall poor diet quality, shifts in sleep patterns, and excess weight—triggers that shape health trajectories in adolescence for years to come.

How it was researched

• The analysis was performed separately for boys and girls: first, bivalent comparisons (chi-square), then multivariate logistic regression with the inclusion of dietary, behavioral and psychosocial variables. This approach helps to see the "pattern" of factors without overlaps (collinearity), for example, to separately assess the contribution of components of the Mediterranean diet (fruits, vegetables, olive oil).

What does this mean for practitioners (parents, schools, doctors)

• Focus on breakfast + "Mediterranean" profile: whole grains, dairy/alternatives, fruits/berries, nuts; olive oil - in the home diet as the "default oil".
• Sleep hygiene: consistent bedtime/wake-up time, limiting screen time in the evening.
• Screen time: reasonable limits, especially on weekdays.
• Teens are not "unisex": girls are more likely to skip breakfast; they may benefit from specific focuses (including work on body image and anxiety). For boys, focus on weight, real circadian rhythms, and "machine snacks."
• For schools: accessible “smart breakfast” in the canteen/cafe and communication with parents reduces barriers (logistics of morning time, finances, taste preferences). (Practical conclusions are based on the patterns of associations identified in the work.)

Limitations to keep in mind

• A cross-sectional design does not prove causality: we see relationships, not "what causes whom."
• Self-reports of food, sleep, and screens are always vulnerable to memory and socially desirable responses.
• Regional sample (Castilla-La Mancha) - carefully transferring the results to other countries/cultural contexts.

Conclusion

A regular breakfast for teenagers is a "beacon" of the overall quality of their diet and daily routine. Where there is an empty plate in the morning, shortcomings of the Mediterranean diet, lack of sleep, too many screens and excess weight are more often found. This means that targeted, gender-sensitive measures - from school programs to family practices - are not a trifle, but an investment in health.

Source: Romero-Blanco C. et al. Why Do Adolescents Skip Breakfast? A Study on the Mediterranean Diet and Risk Factors. Nutrients. 2025;17(12):1948. DOI: 10.3390/nu17121948.