Summary

Overfeeding and overeating

If you eat more food than you need to maintain body weight, you are overfeeding or overeating. The two concepts are similar, yet not exactly the same. Overfeeding implies that a person is feeding someone else. In the context of this study collection, researchers are overfeeding study participants. Overeating implies that a person is eating "too much" on his or her own accord.

Quick overview of the science

Body fat and lean mass typically increase during overfeeding. Though, it depends on how much protein one is consuming (i.e. Bray et al., 2012).

Protein is a special macronutrient. The body does not necessarily gain fat when overfeeding protein.

Overfeeding fats and carbs typically leads to similar gains in body weight and body fat

Overfeeding on nuts leads to unexpectedly little body fat gain

The body will often partially compensate for excess energy intake by increasing energy expenditure (i.e. eat more, move more). This can help limit fat gain.

The Science of Overfeeding

In the scientific literature, overfeeding is typically done by estimating how much energy the subjects expend on a daily basis (Total Daily Energy Expenditure). Then, the scientists ask the subjects to eat more food than usual, or the food could also be provided to the subjects (aka feeding studies).

From there, they can measure how much more energy the subjects consumed compared to their habitual diet.

Some studies are done in metabolic wards where the scientists can control most relevant aspects of a subject’s life, such as physical movement, exercise, other activities, and food intake. Search for “metabolic ward” to find these studies.

Overfeeding studies are interesting because they allow researchers to measure how the body reacts to energy excess.