Food intake and blood glucose in normal and diabetic cats fed ad libitum

Abstract

Ten diabetic cats were studied at intervals for up to 12 months with twice-daily insulin injections. Ten clinically healthy cats were also studied. Diets fed were based on the individual cat's performance, using mainly commercial dry or canned cat foods and fresh meat. In most cases more than one food was offered. Food was given fresh twice daily, and the cats allowed to eat ad libitum. The food intake and blood glucose were measured every 2 h in diabetic cats after insulin injection and in diabetic and normal cats without insulin injections. Food was quantified by the energy consumed (kJ ME), crude protein (g), crude fat (g), and carbohydrate (g). The blood glucose in 10 diabetic cats was measured for 2 h following a 20-min meal. Both diabetic cats and normal cats showed similar patterns of eating, with a higher food intake in the 2 h after fresh food was placed. Both groups of cats ate multiple small meals spread through the day and night. There was little or no correlation between the blood glucose and the amount of food consumed over the previous 2-h period, in insulin- or non-insulin-treated diabetic cats, or in normal cats. An overnight fast did not significantly alter morning blood glucose in diabetic cats. No demonstrable appetite stimulation occurred following an occurrence of low blood glucose; however, recorded incidences were few. No post-prandial hyperglycaemia was seen in the 10 diabetic cats during a 2-h period following the ingestion of typical cat foods.

Fig 1.

Box plot of energy intake for normal and diabetic cats over a 24-h period. The ‘box’ shows the 25–75% interquartile range, with the horizontal line in the box showing the median. The ‘whiskers’ show the 5–95% range, with dots showing outlying data points.

Fig 2.

Box plot of the number of 2-h intervals during which non-diabetic and diabetic cats ate food over a 24-h period. For description of box format, see Fig 1.

Fig 3.

Median percentage of total daily food intake in 10 twice-daily insulin-treated diabetic cats (▪) and 10 non-diabetic cats (□), given fresh food daily.

Fig 4.

Typical pattern of blood glucose (——) and food intake (as energy ingested, □) over 24 h in an insulin-treated diabetic cat.

Fig 5.

Box plot of variation in blood glucose from baseline after a 20-min meal in 10 diabetic cats. For description of box format, see Fig 1.