The OMAD Diet – Foods Permitted During The One-Meal-A-Day Plan

The OMAD diet (also known as One-Meal-A-Day plan) is a pattern of eating that has become quite popular in recent years. A large number of people use it to shed weight or boost their metabolism, but it must be practiced correctly to avoid dire consequences. Read below to learn more about the requirements and restrictions which need to be fulfilled.

At its core, the diet restricts those who practice it to one meal per day, which has to be consumed in a one hour window. From a more practical perspective, it means that 23 hours of fasting periods will take place between the meals, and this fast encourages the body to burn fat as an alternate source of energy.

Foods Permitted During The OMAD Diet

It is worth noting that the basic version of the diet doesn’t mention what should be consumed at what should be avoided, as the focus is placed on the fasting. There are a series of foods that should be consumed when this diet is used since they offer more benefits in the long run. Among them we can count:

• Vegetables like broccoli, cabbage, turnip, beetroot, lettuce, sweet potatoes, and spinach.
• Fruits: mango, pineapple, grapes.
• Foods that are rich in proteins: mushrooms, beans, eggs, chicken breast. Integral dairy products are also recommended: full-fat yogurts, feta cheese, cheddar cheese, buttermilk
• Sources of fat and oils: olive and sunflower oils, peanut butter, almonds, walnuts, pistachios, pumpkin seeds, sunflower seeds.

What You Should Avoid When Following This Diet

Some foods should be avoided. This list includes carbonated soft drinks, low-fat dairy, white rice, butter, margarine, mayonnaise, cashew nuts, and heavily processed foods like salami and jelly.

Keep in mind that while the OMAD diet does offer certain benefits, it may not be suitable for everyone. Special attention must be paid to the number of proteins and carbs that are consumed, with the former having to be considerably higher than the latter.

What Research Says About OMAD and Health Outcomes

The scientific evidence on eating one meal a day specifically is limited compared to broader intermittent fasting research. A study published in Nutrition Reviews found that prolonged fasting periods can improve insulin sensitivity and reduce markers of inflammation. However, a 2022 study in the Journal of the Academy of Nutrition and Dietetics raised concerns that extreme meal restriction patterns like OMAD may increase the risk of disordered eating behaviors, particularly in individuals with a history of eating disorders.

One notable study from the American Journal of Clinical Nutrition compared participants eating one meal versus three meals daily with equivalent caloric intake. The single-meal group showed greater reductions in fat mass but also experienced significantly higher blood pressure and elevated LDL cholesterol compared to the three-meal group. These findings suggest the metabolic effects of OMAD are more nuanced than simple calorie restriction.

Who Should Avoid the OMAD Diet

OMAD is not appropriate for everyone. Individuals with diabetes, particularly those on insulin or sulfonylureas, face serious hypoglycemia risk with prolonged fasting. Pregnant or breastfeeding women have increased caloric and nutrient demands that are extremely difficult to meet in a single meal. People with a history of eating disorders may find that the rigid restriction reinforces unhealthy patterns. Children and adolescents should never follow OMAD as their growing bodies require consistent nutrition throughout the day.

Athletes and highly active individuals may also struggle with OMAD. Consuming sufficient protein for muscle recovery and repair, typically 1.6 to 2.2 grams per kilogram of body weight for active people, in a single sitting can cause significant gastrointestinal discomfort and may impair protein synthesis compared to distributing intake across multiple meals.

Practical Tips for Trying OMAD Safely

If you decide to try OMAD after consulting with a healthcare provider, prioritize nutrient density in your single meal. Focus on lean proteins, complex carbohydrates, healthy fats, and a variety of colorful vegetables to maximize micronutrient intake. Consider using a larger plate or multiple courses to fit adequate nutrition into your eating window. Stay well hydrated throughout the fasting period with water, black coffee, or unsweetened tea.

Start gradually rather than jumping directly into OMAD. Begin with a 16:8 intermittent fasting pattern and progressively narrow your eating window over several weeks. This approach allows your body to adapt and helps you identify whether extreme restriction is sustainable or triggers negative physical and psychological responses.

Frequently Asked Questions

How many calories should you eat on OMAD?

Your caloric needs on OMAD remain the same as any other dietary pattern and depend on your age, sex, activity level, and goals. Most adults need between 1,600 and 2,400 calories daily. The challenge with OMAD is consuming adequate calories in one sitting, as many people unintentionally undereat, which can slow metabolism and cause nutrient deficiencies over time.

Will OMAD slow your metabolism?

Short-term OMAD likely does not significantly affect metabolic rate. However, if OMAD leads to chronic caloric restriction below your body’s needs, adaptive thermogenesis can occur, where your body reduces energy expenditure to conserve resources. Maintaining adequate caloric intake within your single meal is essential to prevent metabolic adaptation.

Can you exercise while doing OMAD?

Yes, but timing and intensity require careful consideration. Low to moderate exercise during the fasting period is generally tolerable. High-intensity or resistance training is best performed close to your eating window to ensure adequate fuel for performance and nutrients for recovery. Listen to your body and reduce intensity if you experience dizziness, excessive fatigue, or impaired performance.

Is OMAD better than other intermittent fasting methods?

Current evidence does not support OMAD as superior to less restrictive fasting patterns like 16:8 or 5:2 for weight loss or health outcomes. The 16:8 method offers similar metabolic benefits with greater flexibility and lower risk of nutrient deficiency. The best dietary pattern is one you can maintain consistently while meeting your nutritional needs.