Final answer:
To create an inversion of the provided sentence, reorder it to emphasize the reason for making breakfast, resulting in the sentence: 'At least to have something that would give them energy, they make themselves some breakfast.'
Step-by-step explanation:
To convert the sentence 'They make themselves some breakfast to at least have something that will give them energy.' into an inversion, you could say: 'At least to have something that would give them energy, they make themselves some breakfast.' This sentence structure brings the purpose (having energy) to the forefront, emphasizing the reason behind making breakfast.