Pre-Pregnancy diet may shield kids from obesity

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Maternal inclusion Criteria: * Maternal pre-pregnancy BMI 27.0-44.9 kg/m\^2 * Maternal age range 18-38 years * Not pregnant or breastfeeding Paternal Inclusion Criteria - full protocol (optional participation): * Paternal pre-pregnancy BMI 18.5-44.9 kg/m\^2 * Paternal age range 18-55 years * Biological father Parental Inclusion Criteria: * Planning pregnancy within 1 year * Provided voluntary informed consent * Danish or English speaking * Intention to permit the planned offspring to participate in the follow-up study * Able to store biological samples from the offspring at home in the freezer in a box given by the study personnel Parental Exclusion Criteria: * Diabetes mellitus (Type 1 or 2) * Previous or present eating disorder * Allergy towards ingredients in the very low calorie diet products * Severe heart, liver or kidney disease * Conception by in vitro fertilization (intrauterine insemination allowed) * ≥4 consecutive spontaneous pregnancy loss (female) * Having tried to conceive or prior time to pregnancy of more than 12 months * Any medical condition or concomitant medication as judged by the medical responsible * Adherence to vegan diets or other diets interfering with the dietary guidelines in the study * Participation in other clinical trial * Engagement in elite sports or similar strenuous exercise ≥5 h/week * Blood donation or transfusion within the past month before baseline * Blood donation during the study * Inability or unwillingness to follow the study protocol and instructions given by the study personnel * Pregnancy registered between baseline visit and 4 weeks after the baseline visit (urinary analysis with dipstick) A detailed description of the exclusion criteria is given below: Medical conditions as known by the participant: * Diabetes mellitus (type 1 and 2) * History or diagnosis of eating disorder (e.g. restrained eating, disinhibition, emotional eating) * Any significant medical condition as assessed by the investigator (e.g. dysregulated thyroid disease or reproductive diseases) * Any significant psychiatric disorder (i.e. schizophrenia, bipolar disease or depression) as assessed by the investigator * Severe chronic heart, liver and kidney disease * Polycystic ovary syndrome with irregular cycle * Amenorrhea * Severely reduced semen quality incl. azoospermia Medication: \- Current use of medication or use within the previous three months with a potential to affect body weight or pregnancy as judged by the investigator (e.g. systemic corticoids) Personal/other: * Having tried to conceive or prior time to pregnancy of more than 12 months * Weight changes ± 5% three months prior to inclusion * Severe food allergies, food intolerances or dislike expected to interfere with the study, including allergy towards ingredients in the VLCD products * Engagement in elite sports or similar strenuous exercise ≥5 h/week * Blood donation or transfusion within the past month before baseline * Planned blood donation for other purpose than this study during participation * Alcohol abuse, as judged by the investigator, within the previous 12 months * Drug abuse, as judged by the investigator, within the previous 12 months * Psychological or behavioral problems which, in the judgement of the investigator, would lead to difficulty in complying with the study protocol * Participation in other clinical trials within the past three months or intention to do so during the study, which are judged by the investigator to affect the present study * Unable to consume the interventional product for religious reasons, swallowing disorders, other physiological reasons or any other reasons for not being able to follow the recommended diet * Inability or unwillingness to give written informed consent or communicate with study personnel * Inability or unwillingness to follow the study protocol and instructions given by the study personnel * Illiteracy or inadequate understanding of Danish or English language. * Any other condition that judged by the investigator may interfere with the adherence to the study protocol