It is widely believed that exposure to sweetened foods and beverages stimulates the liking and desire for sweetness. Here we provide an updated review of the empirical evidence from human research examining whether exposure to sweet foods or beverages influences subsequent general liking for sweetness (‘sweet tooth’), based on the conclusions of existing systematic reviews and more recent research identified from a structured search of literature. Prior reviews have concluded that the evidence for a relationship between sweet taste exposure and measures of sweet taste liking is equivocal, and more recent primary research generally does not support the view that exposure drives increased liking for sweetness, in adults or children. In intervention trials using a range of designs, acute exposure to sweetness usually has the opposite effect (reducing subsequent liking and desire for sweet taste), while sustained exposures have no significant effects or inconsistent effects. Recent longitudinal observational studies in infants and children also report no significant associations between exposures to sweet foods and beverages with measures of sweet taste preferences. Overall, while it is widely assumed that exposure to sweetness stimulates a greater liking and desire for sweetness, this is not borne out by the balance of empirical evidence. While new research may provide a more robust evidence base, there are also a number of methodological, biological and behavioural considerations that may underpin the apparent absence of a positive relationship between sweetness exposure and liking.

This study evaluated changes in the use of sweeteners over one decade and the relationship between socio-demographics, diet and weight status with the type of sweetener. Data came from the Brazilian National Dietary Surveys of 2008–2009 and 2017–2018, including ≥ 10-year-old individuals (n 32 749; n 44 744, respectively, after excluding pregnant and lactating women). The use of table sugar, non-caloric sweeteners (NCS), both or none was reported through a specific question. Food consumption was assessed using two non-consecutive food records (2008–2009) and 24-h recalls (2017–2018). For the last survey, means of energy, macro and micronutrient intake, food groups’ contribution (%) to daily energy intake and age- and energy-adjusted nutrient intake were estimated according to the type of sweetener used. Differences in means and proportions across the categories of sweeteners used were evaluated based on the 95 % CI. All analyses were stratified by sex and considered sample design and weights. Over 10 years, the use of table sugar decreased by 8 %, while the habit of not using any sweetener increased almost three times, and the use of NCS remained stable. Larger reductions in the use of table sugar were observed in the highest income level and among men. Regardless of sex, compared with NCS users, table sugar users had greater mean intake of energy, carbohydrates and added sugar and lower micronutrient intake means. Although table sugar is still the most used sweetener, the increased choice of ‘no sweetener’ is noteworthy in Brazil.

The effect on cognitive test scores of generating differences in postprandial glycaemia using test foods or beverages has been inconsistent. Methodological issues may account for some of the variable results requiring further investigation using strong study designs into the relationship between glycaemia and cognitive functioning. The objective of this study was to determine the effects of postprandial glycaemia on cognitive function by examining cognition after consumption of foods that differ only by the rate of digestion of available carbohydrate in a population of young adults. In a double-blind, randomised, crossover trial, sixty-five participants received trifle sweetened either with a higher-glycaemic index (GI) sugar (sucrose; GI 65) or a lower-GI sugar (isomaltulose; GI 34). Cognitive tests were completed prior to trifle consumption, and 60 and 120 min after. There was no between-trifle difference at 60 min in performance on free word recall (0·0 (95 % CI –0·6, 0·5)), short delay word recall (0·0 (95 % CI –0·5, 0·5)), long delay word recall (0·0 (95 % CI –0·6, 0·6)), letter–number sequence recall (0·3 (95 % CI − 0·2, 0·7)) and visuo-spatial recall (–0·2 (95 % CI –0·6, 0·2)) tests. At 120 min, no difference was detected in any of these tests. The participants performed 7·7 (95 % CI 0·5,14·9) s faster in Reitan’s trail-making test B 60 min after the higher-GI trifle than the lower-GI trifle (P = 0·037). Our findings of a null effect on memory are generally consistent with other works in which blinding and robust control for confounding have been used.

Studies on the intake of different types of carbohydrates and long-term mortality are sparse. We examined the association of starch, total and each type of sugar and free sugars with the risk of total and cause-specific mortality in a cohort of the general population in Japan. Study subjects were 29 079 residents from the Takayama Study, Japan, who responded to a self-administered questionnaire in 1992. Diet was assessed by a validated FFQ at the baseline. Mortality was ascertained during 16 years of follow-up. We noted 2901 deaths (974 cancer related and 775 cardiovascular related) in men and 2438 death (646 cancer related and 903 cardiovascular related) in women. In men, intake of starch was inversely associated with total mortality after controlling for covariates (hazard ratio (HR) for the highest quartile v. lowest quartile: 0·71; 95 % CI 0·60, 0·84; Ptrend < 0·001). Intakes of total sugars, glucose, fructose, sucrose, maltose and free and naturally occurring sugars were significantly positively associated with total mortality in men (HR for the highest v. lowest quartile of total sugar: 1·27; 95 % CI 1·12, 1·45; Ptrend < 0·0001). Similar relations were observed for cardiovascular mortality and non-cancer, non-cardiovascular mortality in men. In women, there was no significant association between any type of carbohydrates and mortality except that intake of free sugars was significantly positively associated with total and non-cancer, non-cardiovascular mortality. Data suggest that the high intake of starch reduces mortality, whereas the high intake of sugars, including glucose, fructose and sucrose, increases mortality in Japanese men.

Currently the world is facing an incredibly costly epidemic of obesity. Almost two-thirds of UK adults are either overweight or obese with estimated financial costs to the UK economy alone of £27 billion per year. While fundamentally obesity is a disorder of energy balance, several decades of research has demonstrated that maintaining energy balance is much more complex than the ‘energy in equals energy out’ equation that was once touted. The purpose of the 2018 Nutrition Society Summer Conference, ‘Getting energy balance right’ was to provide insight into the numerous factors influencing energy balance, considering varying needs across the lifespan, while highlighting advances and gaps in knowledge. Papers presented in this issue illustrate the wide range of factors involved in maintaining energy balance, including: epigenetics, the gut microbiome, physical activity and dietary factors including sugar. Given the complexity of energy balance, systems approaches were highlighted as useful for both understanding metabolism and pathophysiology, and for understanding how public health interventions to treat and prevent obesity should be implemented. The meeting concluded that numerous stakeholders, from individuals, to schools, industry and government, have roles to play in fostering a positive food environment that facilitates the maintenance of energy balance throughout the lifespan.

Formaldehyde is a precursor of sugars, which are compounds essential in all forms of life and a necessary molecule for prebiotic processes. This work focuses on evaluating the stability of formaldehyde exposed to a high radiation field simulating prebiotic conditions on primitive Earth, such as the ocean or shallow waters. Formaldehyde may have been formed from reactions in the atmosphere and from rainout processes reached water bodies. In our experiments, we employed γ radiation and found that formaldehyde was labile towards radiation and decomposed even at low irradiation doses due to the fact that aldehyde/hydrate groups present in formaldehyde structure are very reactive under irradiation. However, after exposing this molecule to several doses of irradiation, we detected the formation of formic acid and glycolaldehyde – both of which are of prebiotic interest. We also observed formaldehyde regeneration by one of its radiolytic products: formic acid.

Horsenettle was described quantitatively in two grazed bermudagrass pastures for two years. Six times from April through October, plants were counted, phenologically documented, and tops were harvested for estimation of above-ground phytomass. Roots were sampled for carbohydrate, N fraction, and macronutrient analyses. Top growth, flowering, fruiting, and chemical composition were similar between sites within years, but differed between years. Starch and total non-structural carbohydrates in roots increased following reproductive periods both years. Root concentrations of protein and non-protein N increased and concentrations of P decreased in August and September in one year only. Analysis of the relationship between seasonal trends in carbohydrate fluctuation and pasture management practices suggests that systemic herbicide application in mid-summer may lead to more effective control than application in spring.

Four days after treatment of corn (Zea mays L. 'SX111′) seedlings with BAS 9052 OH {2 - [1-(ethoxyimino) butyl] - 5 - [2 - (ethylthio) - propyl] - 3 - hydroxy - 2 - cyclohexene-1 - one} growth was inhibited and a purple color developed in the leaves. Low dosages (0.02 and 0.04 kg/ha) caused bleaching of the newly expanding leaves. Dosages higher than 0.04 kg/ha caused significant reductions in length and fresh and dry weights of both shoots and roots. Anthocyanin and total - sugar content increased, whereas chlorophyll accumulation and respiratory activity were reduced by herbicide treatment. BAS 9052 OH did not alter the mitotic index of corn root tips, but induced binucleate cells by preventing cell-plate and -wall formation. In some cells, the daughter nuclei were reoriented with respect to the longitudinal axis of the cells, and in others, the nuclei failed to migrate to the poles. These physiological and cytological effects of BAS 9052 OH on corn seedlings may be responsible for the phytotoxic action of the herbicide on grasses.

This study explored associations between free sugars intake (using non-milk extrinsic sugars as proxy) and nutrient intakes among children aged 1·5–18 years in the UK National Diet and Nutrition Survey 2008–2012. Dietary records were completed by 2073 children (95 % completed 4 d). Mean free sugars intakes (% energy) were 11·8, 14·7 and 15·4 % in the 1·5–3, 4–10 and 11–18 years age groups, respectively. Nutrient intakes and nutrient density were compared across quintiles (Q1–Q5) of free sugars intake (% energy) within each age group. Energy intake rose from Q1 to Q5 of free sugars, whereas percentages of energy intake from fat, SFA and protein dropped. Associations with micronutrients (mg/d or mcg/d) were mostly non-significant, but among 11–18-year-olds there were significant negative associations with Zn, Se, Fe, Cu, and vitamin A and D. There were stronger negative associations with micronutrient density (mg/mcg per 4·18 MJ) for most nutrients in all age groups. Associations with vitamin C were positive. Results were similar after excluding misreporters. Children aged 4–18 years who consumed average amounts of free sugars or above (>13 % energy or Q3–Q5) had lower diet quality than those consuming <10 % free sugars (Q1), but there were insufficient data to assess diets with 5 % free sugars. High consumers obtained a higher proportion of free sugars from soft drinks, fruit juice and sugar confectionery and less from breakfast cereals. Ultimately, nutrient intakes depend on the total dietary pattern; however, reducing overconsumption of sugary foods and drinks with low nutrient density may help improve diet quality.

Circumstantial evidence suggests that substitution of glucose or sucrose by the low-glycaemic index sugar galactose in the diet may lead to greater thermogenesis and/or fat oxidation. Using ventilated hood indirect calorimetry, we investigated, in twelve overnight-fasted adults, the resting energy expenditure (REE) and respiratory quotient (RQ) for 30 min before and 150 min after ingestion of 500 ml of water containing 60 g of glucose, fructose or galactose in a randomised cross-over design. REE increased similarly with all three sugars, reaching peak values after 50–60 min, but its subsequent fall towards baseline values was faster with galactose and glucose than with fructose (P < 0·001). RQ increased with all three sugars, but to a much greater extent with galactose and fructose than with glucose, particularly after 1 h post-ingestion. When ingested as a sugary drink, postprandial thermogenesis and utilisation of fat after galactose are not higher than after glucose or fructose.

The study of unknown and therefore unexploited genetic material from landraces and wild relatives could be essential to help modern plant breeders to respond to ongoing requirements and new challenges in food production. The present study evaluates the most relevant physicochemical values and nutrient contents of a genetically unique array of traditional melon varieties, cultivated in Spain at least since the 19th century, and compares them with modern melon hybrids available on the market. This research is complemented with an assessment of variety, environment and repetition effects on each trait to determine their stability. Spanish melon landraces displayed extraordinary diversity with respect to juiciness (70.59–95.97 g/100 g water fresh weight), firmness (20.75–149.89 N), soluble solids content (9.57–16.53 °Brix), pH (5.04–6.38), total sugars (360.21–877.36 mg/g dry weight), carotenoids (0.01–2.05 μg/g fresh weight) and ascorbic acid values (7.55–44.33 mg/100 g fresh weight). A subset of these landraces, belonging to Piel de Sapo and Rochet market classes, revealed remarkably superior values of ascorbic acid in comparison with all commercial varieties, doubling ascorbic acid values with respect to their corresponding market class. Furthermore, most of these landraces exhibited high acidity and accumulated high levels of sugars, fulfilling those sensory and physicochemical characteristics that researchers and breeders have spent many years seeking. The possibilities of these landraces to be used in improvement projects are innumerable; they should be surely taken into account in the near future.

The typical dietary supply of total fat, fatty acids, starch, sugars, polyols and dietary fibre in Sweden was assessed from analyses of market baskets (MB) purchased in 2005 and 2010. MB were based on food balance sheets, with each basket comprising about 130 foods, which represented more than 90 % of annual dietary supply. Foods were divided into ten to twelve categories. In 2010, total fat contributed 34 % of energy (E%), SFA 14·3 E%, MUFA 12·8 E%, PUFA 4·6 E%, n-6 fatty acids 3·6 E%, n-3 fatty acids 1·0 E% and trans-fatty acids (TFA) 0·5 E%. Glycaemic carbohydrates contributed 47 E%, monosaccharides 9 E%, sucrose 11 E%, disaccharides 15 E% and total sugars 24 E%. Added sugars contributed about 15 E%. Dietary fibre content was about 1·7 g/MJ in the 2010 MB. Compared with the 2005 MB, the dietary supply of TFA and dietary fibre was lower, otherwise differences were small. The present MB survey shows that the content of SFA and added sugars was higher than the current Nordic Nutrition Recommendations, while the content of PUFA and especially dietary fibre was lower. TFA levels decreased and dietary supply was well below the recommendations of the WHO. These results emphasise a focus on quality and food sources of fat and carbohydrates, limiting foods rich in SFA and added sugars and replacing them with foods rich in dietary fibre and cis-unsaturated fatty acids.

Carbohydrates provide the major source of energy in the diet and hence the type and amount of carbohydrate consumed is an important consideration for weight control. Recent risk assessments have shown that there is no consistent association between the proportions of energy consumed as carbohydrate and body weight and reinforce the dominance of total energy intake as the primary determinant of body weight. However, they have highlighted evidence that different types of carbohydrate have specific effects on the risk of obesity. Short-term experimental studies suggest that some types of dietary fibre may be linked to increased satiation and cohort studies are supportive of an association between low intakes of fibre-rich, whole-grain foods and weight gain. But these observations are not supported by evidence of effects on body weight in randomised controlled trials, suggesting that high-fibre or whole-grain intake may simply be a marker of a broader dietary pattern. Recent attention has focused on the growing evidence of a positive association between the intake of free sugars and weight gain and particularly the risks linked to consumption of sugar-sweetened beverages (SSB). Given the high population-level intake of free sugars the challenge is to identify actions that will successfully reduce consumption to contribute to reductions in the prevalence of obesity. The present paper considers the range of policy options available, using the Nuffield ladder of intervention to provide a framework for risk management, with a focus on the consumption of SSB. Current policy interventions are largely based around consumer education and encouragement to industry to renovate products to reduce the sugar content of food and drinks and/or reduce portion size, but dietary change has been slow. Further measures, including the use of specific incentives/disincentives may be needed to change consumption patterns, some of which may infringe personal or commercial freedom. For these policies to be implemented will require sustained efforts to create a climate in which such interventions are acceptable or even welcomed by society as an appropriate protection against obesity and other diet-related ill-health.

Introduction. The genus Phoenix has 13 species. Dates from P. dactylifera and P. theophrasti are the only ones that have been characterised so far. The aim of our study was to evaluate the physico-chemical and functional characteristics of date fruits in the Khalal and Rutab stages of P. loureiroi, P. canariensis, P. reclinata and P. roebelenii, and compare them with P. dactylifera. Materials and methods. Two samples of 15 date fruits in the Khalal stage and another 15 date fruits in the Rutab stage were chosen from each species for analyses and quality parameters. Results and discussion. Significant differences in the measured parameters were observed among the different species. Dates of P. dactylifera were larger than those of the other species and had the lowest [seed weight/fruit weight] proportion. In the Khalal stage, dates from P. canariensis and P. dactylifera were yellow, P. loureiroi and P. reclinata were dark yellow to orange, and those of P. roebelenii were brown purple. Dates of P. dactylifera (Rutab stage) showed higher sugar and lower organic acid contents than those of the other dates. Dates of P. reclinata, P. roebelenii and P. canariensis presented values of antioxidant activity and total phenols in the Khalal stage that were very high compared with those of P. dactylifera. These species are used as ornamental palms but their fruits are consumed locally as food. These dates presented high nutritional quality and can be used as novel foods for different purposes, such as snacks or food fortification, especially due to their high value in functional properties.

Protection-based ant–plant mutualisms may vary in strength due to differences in ant rewards, abundance of protective ants and herbivory pressure. We investigated geographical and temporal variation in host plant traits and herbivory pressure at five sites spanning the distribution range of the myrmecophyte Humboldtia brunonis (Fabaceae) in the Indian Western Ghats. Southern sites had, on average, 2.4 times greater abundance of domatia-bearing individuals, 1.6 times greater extrafloral nectary numbers per leaf, 1.2 times larger extrafloral nectary sizes, 2.2 times greater extrafloral nectar (EFN) volumes and a two-fold increase in total amino acid and total sugar concentrations in EFN compared with northern sites. A strong protection-based mutualism with ants occurred at only one southern site where herbivory was highest, suggesting that investments in attracting ants correlate with anti-herbivore benefits gained from the presence of protective ants. Our results confirm a temporally stable north–south gradient in myrmecophytic traits in this ant-plant as several of these traits were re-sampled after a 5-y interval. However, the chemical composition of EFN varied at both spatial and short-term temporal scales suggesting that only repeated measurements of rewards such as EFN can reveal the real spectrum of trait variation in an ant–plant mutualistic system.

The beneficial effects of cocoa on vascular function are mediated by the absorption of monomeric flavanols into the circulation from the small intestine. As such, an understanding of the impact of the food matrix on the delivery of flavanols to the circulation is critical in assessing the potential vascular impact of a food. In the present study, we investigated the impact of carbohydrate type on flavanol absorption and metabolism from chocolate. A randomised, double-blind, three-arm cross-over study was conducted, where fifteen volunteers were randomly assigned to either a high-flavanol (266 mg) chocolate containing maltitol, a high-flavanol (251 mg) chocolate with sucrose or a low-flavanol (48 mg) chocolate with sucrose. Test chocolates were matched for micro- and macronutrients, including the alkaloids theobromine and caffeine, and were similar in taste and appearance. Total flavanol absorption was lower after consumption of the maltitol-containing test chocolate compared with following consumption of its sucrose-containing equivalent (P = 0·002). Although the O-methylation pattern observed for absorbed flavanols was unaffected by sugar type, individual levels of unmethylated ( − )-epicatechin metabolites, 3′-O-methyl-epicatechin and 4′-O-methyl-epicatechin metabolites were lower for the maltitol-containing test chocolate compared with the sucrose-containing equivalent. Despite a reduction in the total plasma pool of flavanols, the maximum time (Tmax) was unaffected. The present data indicate that full assessment of intervention treatments is vital in future intervention trials with flavanols and that carbohydrate content is an important determinant for the optimal delivery of flavanols to the circulation.

Contrary to concerns that fructose may have adverse metabolic effects, there is evidence that small, ‘catalytic’ doses ( ≤ 10 g/meal) of fructose decrease the glycaemic response to high-glycaemic index meals in human subjects. To assess the longer-term effects of ‘catalytic’ doses of fructose, we undertook a meta-analysis of controlled feeding trials. We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library. Analyses included all controlled feeding trials ≥ 7 d featuring ‘catalytic’ fructose doses ( ≤ 36 g/d) in isoenergetic exchange for other carbohydrates. Data were pooled by the generic inverse variance method using random-effects models and expressed as mean differences (MD) with 95 % CI. Heterogeneity was assessed by the Q statistic and quantified by I2. The Heyland Methodological Quality Score assessed study quality. A total of six feeding trials (n 118) met the eligibility criteria. ‘Catalytic’ doses of fructose significantly reduced HbA1c (MD − 0·40, 95 % CI − 0·72, − 0·08) and fasting glucose (MD − 0·25, 95 % CI − 0·44, − 0·07). This benefit was seen in the absence of adverse effects on fasting insulin, body weight, TAG or uric acid. Subgroup and sensitivity analyses showed evidence of effect modification under certain conditions. The small number of trials and their relatively short duration limit the strength of the conclusions. In conclusion, this small meta-analysis shows that ‘catalytic’ fructose doses ( ≤ 36 g/d) may improve glycaemic control without adverse effects on body weight, TAG, insulin and uric acid. There is a need for larger, longer ( ≥ 6 months) trials using ‘catalytic’ fructose to confirm these results.