This systematic review and meta-analysis, spanning studies published between 1995 and 2021, investigates various aspects of lunches brought from home (LBFH) to school by children. These meals, in contrast to those provided by the National School Lunch Program (NSLP), lack strict nutritional standards. Despite the availability of NSLP lunches, ∼40% of US children opt for LBFH. This review aims to assess the food content and nutritional quality of LBFH, their adherence to NSLP standards in terms of nutrition and cost, effectiveness of intervention programs designed to enhance their nutritional quality and parental and student perceptions of LBFH. The comprehensive literature search yielded 28 eligible papers, with 16 included in meta-analysis. LBFH commonly include fruits (50%), yet vegetables (17%) and dairy (25%) are less prevalent. They frequently contain snacks (50%), sweets (48%), and sugar-sweetened beverages (31%). Compared with school lunches, LBFH exhibit lower levels of calcium, protein, iron, fiber, and vitamin A, and higher levels of carbohydrates and saturated fat. Intervention programs had no effect on quality of LBFH. On average, LBFH ($1.81) cost slightly less than lunches served at school ($1.98), without accounting for free/reduced-price meals in the calculation. The cost of school lunch for pre-k and kindergarten children became $11.32, nearly 4 times higher than that of LBFH ($2.92), after replicating the meal at home and accounting for meal preparation time. Parents preferred LBFH over school lunches because of concerns related to the quality of school meals served. This study concludes that LBFH are generally less nutritious compared with lunches provided by NSLP. Future research needs to further explore ways to improve parent perception of NSLP. Especially with many states making free meals available to all children, identifying effective ways in promoting and increasing NSLP participation can ensure more children have access to nutritionally balanced and affordable lunches.
Research Category: Healthy Lifestyles
The Effects of Potato Presentation on Vegetable Intake in School-Aged Children: A Cross-Over Study
Abstract
Vegetables are an essential component of a healthy dietary pattern in children; however, their consumption is often insufficient due to lack of preference. To address this, the influence of combining vegetables (mixed peas and carrots—MPACs) with potatoes, a generally liked food, on overall vegetable consumption among children aged 7–13 years was explored. The research involved a cross-over study design with 65 participants who completed five lunchtime meal conditions, each with different combinations of MPACs and potatoes versus a control (MPACs with a wheat roll). The meals were provided in a cafeteria setting, and plate waste was used to measure vegetable consumption. Anthropometric data and other variables were also measured. Notably, self-reported hunger did not significantly differ between conditions. Meal condition was a significant predictor of MPACs (F = 5.20; p = 0.0005), with MPAC consumption highest when combined with shaped potato faces in the same bowl (+8.77 g compared to serving MPACs and shaped potato faces in separate bowls) and lowest when combined with diced potatoes in the same bowl (−2.85 g compared to serving MPACs and diced potatoes in separate bowls). The overall model for MPAC consumption was influenced by age, height z-score, body fat percentage z-score, and condition (likelihood ratio = 49.1; p < 0.0001). Age had the strongest correlation with vegetable consumption (r = 0.38), followed by male gender, height z-score (r = 0.30), and body fat z-score (r = −0.15). The results highlight the positive impact of combining potatoes with vegetables in school meals, particularly when using shaped potato faces. These findings emphasize the potential of potatoes as a valuable vegetable option in promoting healthier eating habits among children. Additionally, future research could explore the impact of different potato combinations and investigate other factors influencing meal consumption in school settings.
Potato Protein Ingestion Increases Muscle Protein Synthesis Rates at Rest and during Recovery from Exercise in Humans
Abstract:
Exercise enthusiasts have long presumed animal protein to be superior to plant-derived options for muscle protein synthesis due to its essential amino acid profile. While many plant proteins are deficient in one or more essential amino acids necessary for optimal muscle growth and repair, this randomized, double blind, parallel group study showed that plant-derived proteins can still induce strong anabolic responses. Twenty-four young, healthy males between the ages of 20-28 years participated in this study at Maastricht University, The Netherlands. Participants received primed continuous L-[ring -13C6]-phenylalanine infusions while ingesting 30g potato derived protein or 30g milk protein following a single bout of unilateral resistance exercise. Blood and muscle biopsies were collected 5 hours following protein ingestion to assess post-prandial plasma amino acid profiles and mixed muscle protein synthesis rates at rest and during recovery from exercise. Results demonstrated that consuming 30 grams of potato-derived protein concentrate following resistance exercise strongly increased muscle protein synthesis rates to levels that did not differ from the response following the ingestion of an equivalent amount of milk protein concentrate.
Neither Beetroot Juice Supplementation nor Increased Carbohydrate Oxidation Enhance Economy of Prolonged Exercise in Elite Race Walkers
Given the importance of exercise economy to endurance performance, we implemented two strategies purported to reduce the oxygen cost of exercise within a 4 week training camp in 21 elite male race walkers. Fourteen athletes undertook a crossover investigation with beetroot juice (BRJ) or placebo (PLA) [2 d preload, 2 h pre-exercise + 35 min during exercise] during a 26 km race walking at speeds simulating competitive events. Separately, 19 athletes undertook a parallel group investigation of a multi-pronged strategy (MAX; n = 9) involving chronic (2 w high carbohydrate [CHO] diet + gut training) and acute (CHO loading + 90 g/h CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON; n = 10). There were no differences between BRJ and PLA trials for rates of CHO (p = 0.203) or fat (p = 0.818) oxidation or oxygen consumption (p = 0.090). Compared with CON, MAX was associated with higher rates of CHO oxidation during exercise, with increased exogenous CHO use (CON; peak = ~0.45 g/min; MAX: peak = ~1.45 g/min, p < 0.001). High rates of exogenous CHO use were achieved prior to gut training, without further improvement, suggesting that elite athletes already optimise intestinal CHO absorption via habitual practices. No differences in exercise economy were detected despite small differences in substrate use. Future studies should investigate the impact of these strategies on sub-elite athletes’ economy as well as the performance effects in elite groups.
Effect of White Potatoes on Subjective Appetite, Food Intake, and Glycemic Response in Healthy Older Adults
The objective of this study was to determine the effect of white potato cooking methods on subjective appetite, short-term food intake (FI), and glycemic response in healthy older adults. Using a within-subject, repeated-measures design, 20 participants (age: 70.4 ± 0.6 y) completed, in random order, five treatment conditions: three potato treatments (baked potatoes, mashed potatoes, and French fries), an isocaloric control treatment (white bread), or a fasting condition (meal skipping). Subjective appetite and glycemic response were measured for 120 min using visual analogue scales and capillary blood samples, respectively. Lunch FI was measured with an ad libitum pizza meal at 120 min. Change from baseline subjective appetite (p < 0.001) and lunch FI (p < 0.001) were lower after all test treatments compared with meal skipping (p < 0.001), but did not differ among test treatments. Cumulative FI (test treatment + lunch FI) did not differ among treatment conditions. Blood glucose concentrations were higher after all test treatments compared with meal skipping (p < 0.001), but were not different from each other. In healthy older adults, white potatoes suppressed subjective appetite and lunch FI compared with meal skipping, suggesting white potatoes do not bypass regulatory control mechanisms of FI.
Sustained Exposure to High Carbohydrate Availability Does Not Influence Iron-Regulatory Responses in Elite Endurance Athletes
This study implemented a 2-week high carbohydrate (CHO) diet intended to maximize CHO oxidation rates and examined the iron-regulatory response to a 26-km race walking effort. Twenty international-level, male race walkers were assigned to either a novel high CHO diet (MAX = 10 g/kg body mass CHO daily) inclusive of gut-training strategies, or a moderate CHO control diet (CON = 6 g/kg body mass CHO daily) for a 2-week training period. The athletes completed a 26-km race walking test protocol before and after the dietary intervention. Venous blood samples were collected pre-, post-, and 3 hr postexercise and measured for serum ferritin, interleukin-6, and hepcidin-25 concentrations. Similar decreases in serum ferritin (17–23%) occurred postintervention in MAX and CON. At the baseline, CON had a greater postexercise increase in interleukin-6 levels after 26 km of walking (20.1-fold, 95% CI [9.2, 35.7]) compared with MAX (10.2-fold, 95% CI [3.7, 18.7]). A similar finding was evident for hepcidin levels 3 hr postexercise (CON = 10.8-fold, 95% CI [4.8, 21.2]; MAX = 8.8-fold, 95% CI [3.9, 16.4]). Postintervention, there were no substantial differences in the interleukin-6 response (CON = 13.6-fold, 95% CI [9.2, 20.5]; MAX = 11.2-fold, 95% CI [6.5, 21.3]) or hepcidin levels (CON = 7.1-fold, 95% CI [2.1, 15.4]; MAX = 6.3-fold, 95% CI [1.8, 14.6]) between the dietary groups. Higher resting serum ferritin (p = .004) and hotter trial ambient temperatures (p = .014) were associated with greater hepcidin levels 3 hr postexercise. Very high CHO diets employed by endurance athletes to increase CHO oxidation have little impact on iron regulation in elite athletes. It appears that variations in serum ferritin concentration and ambient temperature, rather than dietary CHO, are associated with increased hepcidin concentrations 3 hr postexercise.
Potato Protein Isolate Stimulates Muscle Protein Synthesis at Rest and with Resistance Exercise in Young Women
Skeletal muscle myofibrillar protein synthesis (MPS) increases in response to protein feeding and to resistance exercise (RE), where each stimuli acts synergistically when combined. The efficacy of plant proteins such as potato protein (PP) isolate to stimulate MPS is unknown. We aimed to determine the effects of PP ingestion on daily MPS with and without RE in healthy women. In a single blind, parallel-group design, 24 young women (21 ± 3 years, n = 12/group) consumed a weight-maintaining baseline diet containing 0.8 g/kg/d of protein before being randomized to consume either 25 g of PP twice daily (1.6 g/kg/d total protein) or a control diet (CON) (0.8 g/kg/d total protein) for 2 wks. Unilateral RE (~30% of maximal strength to failure) was performed thrice weekly with the opposite limb serving as a non-exercised control (Rest). MPS was measured by deuterated water ingestion at baseline, following supplementation (Rest), and following supplementation + RE (Exercise). Ingestion of PP stimulated MPS by 0.14 ± 0.09 %/d at Rest, and by 0.32 ± 0.14 %/d in the Exercise limb. MPS was significantly elevated by 0.20 ± 0.11 %/d in the Exercise limb in CON (P = 0.008). Consuming PP to increase protein intake to levels twice the recommended dietary allowance for protein augmented rates of MPS. Performance of RE stimulated MPS regardless of protein intake. PP is a high-quality, plant-based protein supplement that augments MPS at rest and following RE in healthy young women.
Males and Females Exhibit Similar Muscle Glycogen Recovery with Varied Recovery Food Sources
Research has elucidated the impact of post-exercise carbohydrate nutrition and environmental conditions on muscle glycogen re-synthesis. However, research has minimally considered the implications of glycogen recovery in females and has mostly focused on commercial sport nutrition products. The purpose of this study was to determine the effects of varied mixed macronutrient feedings on glycogen recovery and subsequent exercise performance in both sexes. Males (n = 8) and females (n = 8) participated in a crossover study. Subjects completed a 90-min cycling glycogen depletion trial, then rested for 4 h. Two carbohydrate feedings (1.6 g kg−1) of either sport supplements or potato-based products were delivered at 0 and 2 h post-exercise. Muscle biopsies (glycogen) and blood samples (glucose, insulin) were collected during the recovery. Afterwards, subjects completed a 20 km cycling time trial. There was no difference between sexes or trials for glycogen recovery rates (male: 7.9 ± 2.7, female: 8.2 ± 2.7, potato-based: 8.0 ± 2.5, sport supplement: 8.1 ± 3.1 mM kg wet wt−1 h−1, p > 0.05). Time trial performance was not different between diets (38.3 ± 4.4 and 37.8 ± 3.9 min for potato and sport supplement, respectively, p > 0.05). These results indicate that food items, such as potato-based products, can be as effective as commercially marketed sports supplements when developing glycogen recovery oriented menus and that absolute carbohydrate dose feedings (g kg−1) can be effectively applied to both males and females.
Potato Ingestion is as Effective as Carbohydrate Gels to Support Prolonged Cycling Performance
Carbohydrate (CHO) ingestion is an established strategy to improve endurance performance. Race fuels should not only sustain performance, but also be readily digested and absorbed. Potatoes are a whole-food based option that fulfills these criteria yet their impact on performance remains unexamined. We investigated the effects of potato purée ingestion during prolonged cycling on subsequent performance versus commercial CHO gel or a water-only condition. Twelve cyclists (70.7 ± 7.7 kg, 173 ± 8 cm, 31± 9 years, 22 ± 5.1 % body fat; mean ± SD) with average peak oxygen consumption (VO2PEAK)of 60.7 ± 9.0 mL/kg/min performed a 2 h cycling challenge (60-85%VO2PEAK) followed by a time trial (TT, 6kJ/kg body mass) while consuming potato, gel, or water in a randomized-crossover design. The race fuels were administered with U-[13C6]glucose for an indirect estimate of gastric emptying rate. Blood samples were collected throughout the trials. Blood glucose concentrations were higher (P<0.001) in potato and gel conditions when compared to water condition. Blood lactate concentrations were higher (P=0.001) after the TT completion in both CHO conditions when compared to water condition. TT performance was improved (P=0.032) in both potato (33.0 ± 4.5 min) and gel (33.0 ± 4.2 min) conditions when compared to the water condition (39.5 ± 7.9 min). Moreover, no difference was observed in TT performance between CHO conditions (P=1.00). In conclusion, potato and gel ingestion equally sustained blood glucose concentrations and TT performance. Our results support the effective use of potatoes to support race performance for trained cyclists.
Effects of White Potatoes Consumed With Eggs on Satiety, Food Intake, and Glycemic Response in Children and Adolescents
Objective: Short-term studies in adults have shown that white potatoes increase satiety and suppress food intake (FI) compared with several other carbohydrate-containing foods; however, studies are limited in children. The objective was to compare the effects of white potatoes in mixed meals on satiety, FI, and glycemic response in 9-14-year-old children and adolescents. Methods: Using a within-subject, repeated-measures design, 21 children completed five counter-balanced test sessions. After an overnight fast, children consumed one of four isocaloric treatment meals (450 kcal) of French fries, mashed potatoes, or white beans served with a fixed portion of egg omelet (30 g of protein), a control meal with cereal, milk, and bread, or continued to fast (i.e., meal skipping). Subjective appetite was measured using visual analogue scales. FI at an ad libitum pizza meal at 180 min and rest of day diet record were used to measure lunch FI and rest of day energy intake, respectively. Total daily energy intake was calculated by adding the energy intake from the treatment meal, the ad libitum pizza lunch, and rest of day food record. Capillary blood samples were collected to assess glycemic response over 180 min. Results: Change from baseline subjective average appetite scores were lower after mashed potatoes compared with all other treatment conditions (p < 0.001), and higher after French fries compared with white beans (p = 0.04). Lunch FI (kcal) was significantly lower (p < 0.001) after French fries (1010±73) and mashed potatoes (1039±74) compared with the control meal (1257±92) and meal skipping (1235±74). Total daily energy intake (kcal) was lower after French fries compared with the control meal (2228±141 vs. 2624±137; p = 0.04). Change from baseline blood glucose was lower after white beans and French fries compared with mashed potatoes (p < 0.05) and the control meal (p < 0.001). Conclusion: In conclusion, white potatoes with eggs increased satiety, decreased short-term FI, and resulted in similar energy intakes compared with meal skipping.