First, you can get the full free text via https://academic.oup.com/jcem/article/88/8/3577/2845258. Instead of using Google, try using Google Scholar and typing in the title of the paper with the author’s name. Once you have done that you will see the number of versions present and click on that link. If there is a PDF that is free it will show it.
I read the entire paper. There is nothing in the paper to indicate any adverse effect of doubling the protein energy from 15% to 30% insofar as glucose. On the contrary, the HbA1c values were less. Note that these results were in 12 patients with untreated Type 2 diabetes mellitus (T2DM). There was also note an increase in free urinary cortisol as well as blood urea nitrogen (BUN).