It is not necessary to be as strict with children as you would be for yourself. Children are generally more insulin sensitive than adults, which means their bodies can deal with sugars and carbs more efficiently. Focus on whole foods, good sources of protein, lots of good fats (essential for brain development), and getting carbs from nutrient-dense sources.
Our bodies are incredibly adaptive to what you put into it – when you overload it with fats and take away carbohydrates, it will begin to burn ketones as the primary energy source. Optimal ketone levels offer many health, weight loss, physical and mental performance benefits.1There are scientifically-backed studies that show the advantage of a low-carb, ketogenic diet over a low-fat diet. One meta-analysis of low-carbohydrate diets showed a large advantage in weight loss. The New England Journal of Medicine study resulted in almost double the weight loss in a long-term study on ketone inducing diets.