Sweet Dreams or Sleepless Nights? Unpacking Sugar, Sweeteners, and Evening Brews

Question: Does the presence of sugar or artificial sweeteners in an evening tea or coffee alter its effect on sleep onset?

The ritual of an evening cup of tea or coffee is cherished by many, offering a moment of comfort or a final intellectual jolt. However, when sugar or artificial sweeteners enter the picture, questions arise about their impact on sleep onset. The evidence suggests that the presence of sugar, particularly in coffee, is associated with diminished sleep quality [6].

Sugar’s Sleep Shadow

Research focusing on adolescents found a significant link between the consumption of sugar-sweetened coffee and poorer sleep quality. This association was statistically significant, indicating that adding sugar to an evening coffee is not conducive to a restful night [6]. While the exact mechanisms are not fully elucidated in this context, it is widely accepted that caffeine itself is a stimulant, and the addition of sugar can lead to a rapid rise and subsequent fall in blood glucose levels, potentially disrupting sleep architecture [7]. The study by Vézina-Im et al. did not differentiate between evening and other consumption times, but the implication for late-day beverages is notable [6].

The Unsweetened Enigma

The effect of artificial sweeteners on sleep onset in evening beverages remains a less explored territory. While studies have investigated the broader impact of beverage consumption on sleep, specific attention to the role of non-caloric sweeteners in evening teas or coffees is not explicitly detailed in the provided literature [6]. Given the variety of artificial sweeteners available and their differing metabolic pathways, a generalized conclusion about their effect on sleep onset would be premature without more targeted research.

Coffee’s Complex Chemistry

Beyond additives, the inherent properties of coffee can influence its effect. Different coffee species and processing methods can affect the volatile compounds and even the foam stability of espresso [1, 2, 3, 5]. For instance, the lipid content in pure Arabica espresso may contribute to foam destabilization [1]. Furthermore, fermentation protocols, whether aerobic or anaerobic, can influence the chemical composition, including pH and acidity, which in turn might indirectly affect how the body processes the beverage [2]. While these factors contribute to the overall sensory experience and chemical profile of coffee, their direct impact on sleep onset when consumed in the evening, independent of caffeine content, is not clearly established.

Conclusion

While the stimulant properties of caffeine are the primary concern for evening beverage consumption and sleep, the addition of sugar appears to exacerbate negative effects on sleep quality. The role of artificial sweeteners in evening teas and coffees, however, warrants further investigation to understand their specific impact on sleep onset and overall restfulness.

References

[1] — Ernesto Illy, Luciano Navarini — Neglected Food Bubbles: The Espresso Coffee Foam. — 2011-Sep — https://pubmed.ncbi.nlm.nih.gov/21892345/ [2] — Gustavo Galarza, Jorge G Figueroa — Volatile Compound Characterization of Coffee ( — 2022-Mar-21 — https://pubmed.ncbi.nlm.nih.gov/35335365/ [3] — Katarína Poláková, Alica Bobková, Alžbeta Demianová, Marek Bobko, Judita Lidiková, Lukáš Jurčaga, Ľubomír Belej, Andrea Mesárošová, Melina Korčok, Tomáš Tóth — Quality Attributes and Sensory Acceptance of Different Botanical Coffee Co-Products. — 2023-Jul-11 — https://pubmed.ncbi.nlm.nih.gov/37509767/ [4] — Marlene Machado, Iva Fernandes, Ana Fernandes, Liliana Espírito Santo, Cláudia Passos, Aroa Santamarina, Alejandra Cardelle-Cobas, Manuel A Coimbra, Maria B P P Oliveira, Helena Ferreira, Rita C Alves — Impact of In vitro Gastrointestinal Digestion on the Chemical Composition and Prebiotic Potential of Coffee Silverskin. — 2025-Sep-05 — https://pubmed.ncbi.nlm.nih.gov/40911156/ [5] — Faguang Hu, Haohao Yu, Xingfei Fu, Zhongxian Li, Wenjiang Dong, Guiping Li, Yanan Li, Yaqi Li, Bingqing Qu, Xiaofei Bi — Characterization of volatile compounds and microbial diversity of Arabica coffee in honey processing method based on different mucilage retention treatments. — 2025-Jan — https://pubmed.ncbi.nlm.nih.gov/39974542/ [6] — Lydi-Anne Vézina-Im, Dominique Beaulieu, Stéphane Turcotte, Anne-Frédérique Turcotte, Joannie Delisle-Martel, Valérie Labbé, Lily Lessard, Mariane Gingras — Association between Beverage Consumption and Sleep Quality in Adolescents. — 2024-Jan-18 — https://pubmed.ncbi.nlm.nih.gov/38257178/ [7] — Aruna Raju, Madhavan Chandran, Jean Fredrick — Excessive day time sleepiness, poor sleep quality, and their association to caffeine consumption among young Informational Technology professionals. — 2025 — https://pubmed.ncbi.nlm.nih.gov/40861136/