How much fruit is too much? For example, iday all at the same time, as an afternoon snack?
The accurate, but unsatisfying, answer to this question is “It depends”.
It depends on the kinds of fruit you choose, and whether you eat them alone or in conjunction with other foods (veggies, proteins, fatty foods). Fruits contain sugars, predominantly fructose and sucrose, both of which can cause spikes in blood sugar (glucose). Most fruits also contain fibre. The presence of fibre slows the digestion of the sugars. If you eat fruits in conjunction with other foods, the complex carbohydrates, fibre, protein and fat the other foods contain will blunt the impact of the sugars from the fruit on your blood sugar.
It depends on your health, and whether or not you have conditions that might make it advisable to avoid certain kinds of fibre and/or abrupt changes in your blood sugar. If you are diabetic, prediabetic, overweight, obese or prone to hypoglycemia (low blood sugar), you would be better off limiting your fruit consumption to 2 fruits per day, spread throughout the day. When you do eat fruit, you should choose those that have a lower glycemic load, such as strawberries, plums, apricots and grapefruit. You can learn more about glycemic load here:
If you have conditions that affect the digestive system, (IBD, IBS or diverticular disease) you may need to avoid certain kinds of fibre and/or abrupt changes in your fibre intake. Choose carefully with your doctor’s guidance to avoid symptom flares.
If you don’t have any blood sugar problems, and the influx of fibre from the fruit doesn’t make you gassy or disrupt your digestion, then eating 5 pieces at one time may not be an issue. In general, however, it makes sense to think of fruit as “nature’s candy” and to consume it in moderation.