Determining the factors affecting energy metabolism and energy requirement in cancer patients. Thermic effect of a meal and appetite in adults: an individual participant data meta-analysis of meal-test trials. Ravn AM, Gregersen NT, Christensen R, et al. Greater skeletal muscle oxidative capacity is associated with higher resting metabolic rate: results from the baltimore longitudinal study of aging. Investigating sex differences in the accuracy of dietary assessment methods to measure energy intake in adults: a systematic review and meta-analysis. Factors affecting energy expenditure and requirements. National Academies of Sciences, Engineering, and Medicine Health and Medicine Division Food and Nutrition Board Committee on the Dietary Reference Intakes for Energy. Total energy expenditure, energy intake, and body composition in endurance athletes across the training season: a systematic review. Heydenreich J, Kayser B, Schutz Y, Melzer K. Hormonal regulation of metabolism-recent lessons learned from insulin and estrogen. This means your body burns more calories digesting protein than it does digesting carbs or fats. Protein digestion requires 10-30% of the energy content of the ingested protein, while carbohydrates and fats require 5-10% and 0-3%, respectively.

Diet: Your diet is another factor that influences your metabolism.

Regular physical activity increases muscle mass and increases the calories you burn while you’re at rest, or BMR.

Physical activity: People who are more active require more energy than people with low activity levels.

Research shows BMR remains mostly stable from ages 20-60 and then starts to decline after age 60. This is related to muscle tissue loss, lower activity levels, and other age-related metabolic changes.

Age: As we age, our basal metabolic rate tends to decline.

This is because muscle cells burn energy more efficiently than fat cells.

Body composition: People who have more muscle mass have a faster metabolic rate than people with low muscle mass and high body fat levels.

Gender: Men typically require more calories than women because they’re usually larger and have more muscle mass.

However, this isn’t always the case, as certain factors, such as physical activity levels, impact energy needs. For example, a person who’s six feet tall will generally require more calories to sustain their body weight compared to someone who’s five feet tall.

Body size: Larger individuals generally require more energy compared to smaller people.But it sounds like something is going on. It also sounds like the scar tissue was making it a challenge to get a clear idea of what is going on. The scan cannot differentiate between cancer cells or other situations like infection or inflammation that may be causing this activity. It sounds like there was a significant amount of hypermetabolic activity shown on the PET scan results. In addition, not everything that is hypermetabolic is cancer.' When the scan is done, these areas 'light up.' Often, but not always, cancer cells fall into this category of being hypermetabolic. A radioactive substance is given to the patient and this attaches to glucose, which is attracted to cells that are hypermetabolic.

'A PET scan (positron emission tomography) works to identify areas of hypermetabolic activity anywhere in the body. I'm not a doctor, but I might be able to help explain a few things that you've mentioned. I can see that you have quite a few questions after your appointment with your oncologist. – Metastatic breast cancer: Anyone else? You may also be interested in joining this discussion:

Metabolic activity synonym