You know, it's funny, because that study is pro-1 meal and you're using it to argue against it. Those blood glucose levels are from a morning OGTT.
In the present study morning glucose tolerance was impaired when subjects were consuming 1 meal/day compared to 3 meals/day. Fasting (morning) plasma glucose levels were significantly elevated in subjects when they were consuming 1 meal/d compared to 3 meals/d. The latter difference in fasting glucose levels could be explained, in part, by continuing absorption of the greater amount of food consumed in the evening in the subjects on the 1 meal/d diet. Other studies have suggested an adverse effect of meal-skipping diets on insulin sensitivity [20–22]; however, these studies were either epidemiological (with inherent confounds) or involved very short-term (days) changes in diet. Whether the effect of the 1 meal/d diet on glucose tolerance would persist, exacerbate or resolve over time beyond the 2 month experimental diet period of our study is an important question relevant to long-term effects of the diet. However, we did find that the effect of the 1 meal/d diet on glucose tolerance was rapidly reversed upon return to the 3 meal/d diet, indicating that the diet had no long-lasting effect on glucose metabolism.
The OGTTs were performed in the morning. Therefore, when on the 1 meal/d diet the subjects had consumed a much greater amount of food in proximity to the OGTT compared to subjects on 3 meals/d, which could have influenced morning insulin sensitivity. Moreover, circadian variations in glucose tolerance have been documented with tolerance being best in the morning [38]. When not accustomed to a morning meal, and then subjected to a morning OGTT, the subjects eating 1 meal/d may therefore exhibit poorer glucose tolerance compared to those adapted to eating breakfast.
Our findings show that consumption of one unusually large meal per day worsens morning glucose tolerance compared to an isocaloric diet spread across three meals. However, when on 1 meal/d the subjects would have eaten less than those on 3 meals/day if we had not asked them to consume the same amount of food that they normally eat on a 3 meal/d schedule. When rodents are subjected to an alternate day fasting regimen, their overall calorie intake is decreased by 10–30% and they maintain a lower body weight than animals on an ad libitum control diet, and exhibit increased insulin sensitivity and decreased blood pressure [11, 25].Similarly, when maintained on an alternate day calorie restriction diet over a 2 month period, human subjects lost weight and exhibited improved cardiovascular disease and diabetes risk profiles. In the latter study the subjects ate only 400–500 calories on CR days, which resulted in a reduction in plasma leptin levels and an elevation of β-hydroxybutyrate levels only on the CR days, but sustained decreases in plasma insulin levels suggesting improved insulin sensitivity.
Collectively, the available data therefore suggest that meal skipping or intermittent CR diets can result in health benefits including improved glucose regulation, but only if there is an overall reduction in energy intake.
Show me more scientific research that argues against the point you're trying to make, please.