While fruit is a nutritious food with many needed antioxidants, it is still a source of sugar and can limit weight loss. Fruit contains both fructose and glucose in varying ratios depending on the fruit.
Glucose is the primary sugar in starches like grains and potatoes and is the main source for glycogen for our muscles. When muscle glycogen stores are full or the muscles are insulin resistant, excess glycogen is taken by insulin to the fat cells to be stored for later use (body fat).
Fructose replenishes liver glycogen levels but when the liver has enough glycogen, excess fructose is also stored as fat. Over consumption of fructose is generally the cause of non-alcoholic fatty liver disease.
Table sugar and high fructose corn syrup are made up of both of these types of sugar and most of us get plenty of both. So fructose comes into our system even if we haven’t eaten fruit just from common sweeteners and as a hidden ingredient in foods, like many wheat breads and meal replacement shakes.
I generally recommend to my weight loss clients and in my weight loss coaching group to have no more than half a serving, 15g, of net carbohydrates from fruit (carbs minus fiber). Examples of this would be half a grapefruit, a cup of berries or a small apple. To determine the sugar content of your fruit serving use a food app or just Google it.