After the holiday season, many people indulge and abandon dietary limits. It becomes important to reset digestion quickly. Fasting-style days offer a practical path, with a wide range of options available.
At their core, these plans reduce daily intake to one to three foods drawn from a group, such as fruits or vegetables. Typically about two kilograms of product are spread across several smaller meals through the day. Drinking plenty of water is essential; other beverages are usually avoided.
Fasting days bring several benefits. They can create a caloric deficit that helps weight reduction. They also promote fluid and toxin elimination from the body and ease the workload on the digestive tract. With consistent use, they may contribute to a smaller stomach capacity over time, according to Daria Veselova, an endocrinologist at the Be Healthy clinic.
How to pick the right plan
The recommendation is to try different fasting-day options to see what feels best. Some people may thrive on simply an apple with water, while others might find it challenging, notes Ksenia Selezneva, a nutritionist and head of the nutrition department at EMC, speaking with SocialBites.
Because reducing calories can cause weakness, dizziness, fatigue, and concentration lapses, Selezneva suggests that beginners consider fermented dairy products first, if tolerated well. They are among the more satisfying choices, helping ease the transition. For instance, a day can be built around 1–1.5 liters of kefir or plain yogurt with about 2 liters of water. Cottage cheese and kefir can substitute for each other. Mono-diets should not last long, as they may fail to supply essential nutrients and calories for a healthy life, Selezneva cautions.
However, Alexey Kabanov, a consultant nutritionist and deputy director of the ANO Scientific Research Center Healthy Nutrition, labels a kefir-only day as questionable. He warns that too much acidity can upset the stomach, potentially causing heartburn or diarrhea, and that relief from such a plan is temporary and may be a power-day rather than a true solution.
Fasting on porridge is another popular route. Buckwheat, semolina, or oats can be eaten without salt, butter, or sugar, and portions can be divided into five mini meals for the day. Buckwheat is often considered a superfood because it contains nutrients like vitamins K and B6, plus minerals such as potassium, calcium, iron, and phosphorus. It can be especially beneficial for those with heart disease or diabetes, helping moderate blood sugar levels.
Alternatives include days centered on buckwheat or rice, though digestion may be tougher. There are also fruit-and-water days featuring pears, apples, watermelon, or plain water. This approach offers energy and fiber but risks gut discomfort from imbalance, as noted by Kabanov. Consuming 5–7 apples in one day is excessive for the intestines, and merely surviving on water for a day borders on a health risk.
Some see protein-focused fasting as the safest option, providing a bridge to a balanced, ongoing diet. Proteins support recovery after workouts, immune function, and muscle growth. Yet excess protein can burden the kidneys and may raise blood pressure and glucose issues for some. The suggested plan involves eggs for breakfast, fish for lunch, and plant-based proteins for dinner, including legumes and whole grains. Still, such intense single-day fasts are unlikely to be beneficial in the long run, and the overall aim should be a complete, balanced, sustainable diet rather than sporadic experiments on health.
Rules for single-diet days
Veselova emphasizes that mono-diets carry some key guidelines. They should not be followed for more than one to two days but can be used periodically, such as once a month, and medical supervision is advised before starting any mono-diet.
During the initial days of a mono-diet, keeping a food diary helps track emotional responses and bodily signals after meals. Discussing these observations with a doctor allows adjustments to the fasting plan if a particular food does not suit the person. Some fasting options may not be appropriate for people with certain conditions. For example, solely fruit or vegetable days can aggravate stomach acidity and may trigger gastritis or ulcers. Caution is also warranted for those with high blood sugar depending on fruit-based mono-diets.
Contraindications include intolerance to any component of the fasting plan. Lactose intolerance, for instance, makes fermented-dairy days unsuitable. Exacerbations of gastrointestinal diseases, diabetes, pregnancy, and breastfeeding require medical consultation to determine whether a specific fasting day is safe. It is best to avoid fasting during periods of intense physical or mental activity. A careful specialist can help decide if a particular fasting day will be beneficial or if another approach is preferable. Exiting a mono-diet should be gradual, gradually reintroducing lean meats, fiber-rich vegetables, and fermented-dairy products in moderation.
There is another viewpoint: a fasting day is a short-term adjustment for a single day, so a formal exit is not always necessary after a completed cycle. The emphasis remains on establishing a steady, long-term pattern rather than repeating rapid, isolated experiments.
Experts agree that a stable routine aligned with core dietary principles is often more effective than dramatic, brief changes. If someone chooses a temporary overhaul, professional guidance is essential to tailor options to health indicators and personal needs.