This study evaluates how Fast Bar(TM), a specially formulated energy bar, when consumed with coffee or tea, affects the physiological condition in participants after an overnight fasting. Participants will fast for 19 hours (Fast Group), consume a Fast Bar in the night (Night Bar Group) or in the morning (Bar+Coffee and Bar+Tea Groups) after an approximately 15-hour overnight fasting. Participants will be assessed for physiological parameters associated with fasting.

Interest in fasting-based programs (i.e. intermittent fasting) for improvement of health and longevity continues to grow. The short-term fasting (e.g. 12 to 48 hours in duration) utilized in many intermittent fasting programs are considered safe, but some individuals may find them subjectively difficult. As such, the question of whether the benefits of fasting can be obtained while small amounts of food are consumed is of substantial interest.

One commercially available product that is designed to be consumed during periods of intermittent fasting is the Fast Bar™, which stems out of the well-researched fasting-mimicking diet to assist prolonged fasting. The unique formulation of the Fast Bar™ is hypothesized to minimize deviations in metabolic biomarkers associated with a fasting state. This may ease the burdens associated with extended period of fasting. The objective of this study is to evaluate the metabolic and subjective effects of Fast Bar, when consumed with coffee or tea, after a prolonged period of fasting.

Inclusion Criteria:

• Ability and willingness to provide written informed consent;
• Ability and willingness to use Zoom teleconference;
• Ability and willingness to perform the study tests and adhere to study protocol to the best of the participant's knowledge;
• 18-65 years of age (inclusive) at screening;
• BMI 20-35 kg/m2 (inclusive) at screening;
• In good health (as determined by medical history to evaluate acute or ongoing chronic medical diagnoses/conditions that have been present for at least 90 days);
• Habitual breakfast eater (determined with a screening survey: number of breakfasts per week ≥4.

Exclusion Criteria:

• Has any medical disease or condition that, in the opinion of the principal investigator (PI) or appropriate study personnel, precludes study participation* (*Including acute, subacute, intermittent or chronic medical disease or condition that would place the subject at an unacceptable risk of injury, render the subject unable to meet the requirements of the protocol, or may interfere with the evaluation of responses or the subject's successful completion of this trial);
• History of gastric bypass (based on medical history provided at screening);
• Under medications aimed at keeping blood glucose under control (based on medical history provided at screening);
• Type 1 diabetes (based on medical history provided at screening);
• Taking insulin, insulin analogs, or octreotide (based on medical history provided at screening);
• Food allergies which would make the subject unable to consume the food provided (based on medical history and information provided at screening) (participants will be asked to review the ingredient lists for the dinner meal and the Fast BarTM, and to state that they are not allergic to the ingredients to the best of their knowledge);
• Women who are pregnant;
• Alcohol dependency (alcohol intake greater than two drinks per day for women and three drinks per day for men) (based on medical history and information provided at screening).