Restricting sugar or carbohydrate intake does not impact physical activity level or energy intake over 24 h despite changes in substrate use : A randomised crossover study in healthy men and women

Purpose To determine the effects of dietary sugar or carbohydrate restriction on physical activity energy expenditure, energy intake, and physiological outcomes across 24 h. Methods In a randomized, open-label crossover design, twenty-five healthy men (n = 10) and women (n = 15) consumed three diets over a 24-h period: moderate carbohydrate and sugar content (MODSUG = 50% carbohydrate [20% sugars], 15% protein, 35% fat); low sugar content (LOWSUG = 50% carbohydrate [< 5% sugars], 15% protein, 35% fat); and low carbohydrate content (LOWCHO = 8% carbohydrate [< 5% sugars], 15% protein, 77% fat). Postprandial metabolic responses to a prescribed breakfast (20% EI) were monitored under laboratory conditions before an ad libitum test lunch, with subsequent diet and physical activity monitoring under free-living conditions until blood sample collection the following morning. Results The MODSUG, LOWSUG and LOWCHO diets resulted in similar mean [95%CI] rates of both physical activity energy expenditure (771 [624, 919] vs. 677 [565, 789] vs. 802 [614, 991] kcal·d−1; p = 0.29] and energy intake (2071 [1794, 2347] vs. 2195 [1918, 2473] vs. 2194 [1890, 2498] kcal·d−1; P = 0.34), respectively. The LOWCHO condition elicited the lowest glycaemic and insulinaemic responses to breakfast (P < 0.01) but the highest 24-h increase in LDL-cholesterol concentrations (P < 0.001), with no differences between the MODSUG and LOWSUG treatments. Leptin concentrations decreased over 24-h of consuming LOWCHO relative to LOWSUG (p < 0.01). Conclusion When energy density is controlled for, restricting either sugar or total dietary carbohydrate does not modulate physical activity level or energy intake over a 24-h period (~ 19-h free-living) despite substantial metabolic changes. Clinical trials registration ID NCT03509610, https://clinicaltrials.gov/show/NCT0350961

Effect of Plain Versus Sugar-Sweetened Breakfast on Energy Balance and Metabolic Health : A Randomized Crossover Trial

We would like to thank Pippa Heath for her help with randomization, our participants, and Dr. Graham Horgan for statistical advice. Funding Information Economic and Social Research Council. Grant Number: ES/J50015X/1 Biotechnology and Biological Sciences Research Council (BBSRC) GlaxoSmithKline Lucozade Ribena Suntory Kellogg’s Nestlé PepsiCo Sugar Nutrition UK Danone Baby Nutrition the Alpro Foundation Kellogg Europe Unilever Volac International The Collagen Research Institute British Summer FruitsPeer reviewedPublisher PD