Which doesn’t look like what this is.
Some folks get tubby with great ease, and others are string beans no matter what they choose to dine on, and some have been both at different times in their lives.
Whatever the case, someone as heavy as she is, is at much higher risk of numerous health problems.
There are various ways of losing weight. Not all work for everyone, but she really should be encouraged to look into it, for her own personal health.
Calories consumed, calories expended. That is all.
Should anyone find an exception to the first law of thermodynamics... well then, that’s different.