Portion control tools and an app put to the test for weight management

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

Inclusion Criteria: * Body mass index equal or above 27.5 kg/m2 (26.0 kg/m2 for those of Asian descent) * Eating home-made meals at least 5 days a week * Physically and mentally fit as assessed by the study researcher * On-going pharmacological and hormonal treatment is accepted when this does not affect the study parameters (e.g. glucose response, appetite), and when the participant has been in a stable dose for at least 3 months * Agreeing to undergo all the study procedures * Being able to attend in person on 3 clinical investigation days during working hours * Being able to understand and agree to sign the informed consent form Exclusion Criteria: * Being a regular smoker (that is, smoke more than 4 cigarettes a month) * Being pregnant, breastfeeding or planning a pregnancy * Exceed the alcohol consumption limit marked for the corresponding sex (more than 14 units in women and 20 units in men) * Having followed a meal plan for weight loss and/or muscle mass gain in the 3 months prior to the start of the study intervention * Having used a portion measuring instrument (e.g. scale, calibrated plate, etc.) consistently (at least in one main meal for at least 5 days a week) during the 3 months prior to the start of the study intervention * Experiencing a weight change greater than 5% in the last 3 months * History of relevant functional or structural anomalies of the digestive system, such as malformations, angiodysplasias, active peptic ulcers, chronic inflammatory or malabsorption diseases, or history of intestinal or bariatric surgery * Suffer from some type of cancer, currently undergoing treatment for cancer, or when a period of at least 5 years has not elapsed since its eradication * On-going chronic metabolic disease or obesity-related disease, or any systemic intestinal, liver or kidney disease such as type 1 or type 2 diabetes, severe dyslipidemia, uncontrolled thyroid function disorder, cirrhosis, inflammatory bowel disease, untreated anemia, etc. . (will not be excluded due to "fatty liver") * Avoiding, being allergic, or being intolerant to the study foods or their ingredients (lactose free and regular chocolate milkshake) * History of anaphylactic reaction to any food * Taking any nutritional supplementation as a prescription medication that may affect the results of the study * Taking over-the-counter nutritional supplementation (that is, without a medical prescription) that may affect the results of the study, unless the person is willing to stop it during the 6 months of the study duration and only when a minimum washout period of 14 days can be guaranteed prior to the basal measurements being taken * A high incidence of attitudes and behaviors associated with eating disorders, expressed as a score greater than 20 on the 26-item Eating Attitudes Test scale (EAT - 26) * Co-inhabiting with a study participant * For former PORTIONS-3 study participants, when less than 3 months have passed since the last intervention visit (accepted if 3 or more months have elapsed).