**Background:** The COVID-19 pandemic led to worldwide lockdowns that disrupted social habits and lifestyles, including dietary patterns. In Egypt, a strict stay-at-home order was enforced from March 15 to the end of June 2020, closing schools, religious places, airports, and malls. While changes in dietary habits were expected, limited information was available about these changes in the Egyptian population. This study aimed to examine the effects of COVID-19 lockdown on dietary habits among adult Egyptians to inform future public health recommendations.
**Methods:** This cross-sectional study (the Egyptian COVIDiet study, clinical trial NCT04449731) used an online self-administered questionnaire distributed via Google Forms, WhatsApp, Facebook, Twitter, LinkedIn, and ResearchGate through snowball sampling during March–August 2020. The questionnaire included sociodemographic items, the validated 14-item PREDIMED Mediterranean Diet Adherence Screener (MEDAS-14) with modifications (wine intake excluded due to low consumption in Egypt), and 35 in-house questions about changes in dietary habits, physical activity, and body weight during lockdown. Inclusion criteria were adults ≥18 years; exclusion criteria included neonates and people with comorbid conditions (thyroid, diabetes, ascites, active hepatic and renal disorders). Internal validity was assessed with Cronbach's alpha (0.83) via a pilot of 25 individuals who completed the questionnaire twice with 5 weeks between administrations. Data analysis used SPSS version 21, with Student's t-test and Chi-square test for significance (p<0.05).
**Key Results:** A total of 1,010 participants responded: 77.3% female, 67.6% aged 21–35 years, 8.6% ≤20 years, 21.7% aged 36–50, and 2.1% >50 years. By BMI, 36.5% were normal weight, 39.0% overweight, 22.2% obese, and 2.3% underweight. Educational levels: 62.3% university, 31.2% postgraduate, 6.5% secondary. Geographically, 49.9% resided in Alexandria, 33.9% in Delta, 11.3% in Cairo, and 4.9% in other governorates.
BY AGE
Respondents ≤20 years significantly increased intake of carbonated beverages (18.4%), commercial pastries (23%), fried food (36%), and fast food (17%), with a significant rise in body weight (31%) and increased physical activity (19.5%). Those >50 years reported >78% reduction in physical activity, but >60% reported decreased body weight. Participants aged 21–50 (~40%) reported no changes in consumption of carbonated beverages, commercial pastries, fried food, or fast food.
BY BMI
Underweight individuals (n=23) decreased cooking frequency (9%) and increased fast food intake (17.5%) with prominent weight rise (39%). Obese individuals (n=224) increased cooking frequency (46%) and eating time (67.5%) with decreased physical activity (22%) and minimal weight increase (12.5%). At least 50% of normal-weight participants reported no weight gain or changes in physical activity or dietary habits.
BY GENDER
Males increased carbonated beverages (21%) and fast food (14%). Females increased homemade pastries (39%) and cooking frequency (42%). Approximately 40–50% of all participants reported a decline in physical activity and body weight regardless of gender.
BY GEOGRAPHY
Cairo residents increased vegetable intake (47%), fried food intake (40.5%), and cooking frequency (44%), with 19.5% and 41% reporting decreased seafood and commercial pastries intake, respectively. Delta residents increased commercial pastries (20%), homemade pastries (37%), and fried food (43.5%), with 43% increasing cooking frequency. Alexandria residents decreased commercial pastries (34%), homemade pastries (19.5%), and fried food (21%), with 9% decreasing cooking frequency. Approximately 50% of participants from all governorates reported weight decrease.
BY EDUCATION
Participants with secondary education increased carbonated beverages (29%). Approximately 45% of all participants regardless of education level reported decreased body weight, and 33% reported no change. Those with postgraduate education (~40–60%) reported reduced consumption of fast food and carbonated beverages with lower weight gain.
**Clinical Implications:** The study reveals that age, BMI, gender, educational level, and geographical location significantly influenced dietary and physical activity changes during the COVID-19 lockdown in Egypt. Younger adults (≤20 years) are particularly vulnerable to unhealthy dietary shifts and weight gain, while older adults (>50 years) face reduced physical activity. Obese individuals showed increased cooking and eating frequency but reduced physical activity. These findings provide essential information for the Egyptian Ministry of Health to develop targeted recommendations for future lockdowns, emphasizing healthy dietary habits and physical activity to protect health and enhance immune function. Limitations include overrepresentation of northern Egypt (Alexandria and Delta regions), female predominance (77.3%), cross-sectional design preventing causal inference, and inability to measure the magnitude of weight changes.