Answer:
She is highly sensitive to external cues for hunger.
Step-by-step explanation:
Satisfying hunger is a key behavior, but deciding when and what to eat can be influenced by environmental cues, not just how long it has been since the last meal. Visual cues associated with food in TV commercials and street and road ads are known to contribute to overeating. Some people are highly sensitive to these external signs of hunger and end up being influenced and eating more than is healthy for their body.
Millie is a person who has this kind of sensitivity, this is affecting her body and making her overweight, so she needs to lose weight.