Excessive sugar intake in children is a public health concern as this can contribute to unhealthy dietary patterns later in life and increase the risk of excess weight gain and dental caries. There is limited research available on the consumption of sugar in young children in relation to sociodemographic characteristics and anthropometric measures. There is also limited data on the consumption of sugar alternatives such as non-nutritive sweeteners. Thus, the current dissertation aims to comprehensively examine total, free, and added sugar intake in young children (aged 1.5 to 5 y) enrolled in the Guelph Family Health Study. The dissertation initially reviews the complexity of multiple definitions of sugar, health recommendations, and implications for lifelong health of young children. The third chapter then examines how sociodemographic characteristics may predispose young children to higher sugar intake. Specifically, the associations are examined between child age, child sex, child ethnicity, parent number of years living in Canada, annual household income, parent education and parent marital status with total, free and added sugar intakes in young children. In this chapter, child age, child ethnicity and annual household income are found to be crucial influencers of sugar intake in young children. The subsequent chapters focus on a detailed analysis of the effects of sugar intake on anthropometric measures (including body weight, waist circumference, BMI Z-scores and percent fat mass) in young children (1.5 y to < 8 y) cross-sectionally and longitudinally. These chapters report that young children are exceeding current World Health Organization’s recommendations for sugar intake. No statistically significant associations are observed between sugar intake and anthropometrics of young children. Given the efforts to reduce sugar intake using alternatives to sugar and sugar substitutes, this dissertation ends by evaluating the intake of non-nutritive sweeteners in young children. These are found to be low in the diets of young children currently. In conclusion, it is recommended that further research is warranted, especially longitudinal studies to better understand the long-term impact of total, free, and added sugar consumption and non-nutritive sweetener intake in young children.