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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jada.2008.11.027 Byline: Fiona McKiernan, James H. Hollis, George P. McCabe, Richard D. Mattes Abstract: Although thirst and hunger have historically motivated drinking and feeding, respectively, the high and increasing consumption of energy-yielding beverages and energy-diluted foods may have degraded the predictive value of these sensations on ingestive behavior. Our within subject (ie, multiple responses from the same individuals), observational (ie, free-living, with no intervention) study explored the relationships between thirst, hunger, eating, and drinking patterns in 50 weight-stable adults (39 women and 11 men aged 30[+ or -]11 years with body mass index 26.3[+ or -]5.9). Twenty-four-hour dietary recalls were obtained for a consecutive 7-day period. Appetite ratings were recorded hourly, over the same time period, and correlated with hourly energy and fluid intake from food and beverages. Thirst ratings were not correlated with drinking (r=0.03) or energy intake (r=0.08) during the same hour over the 7-day period. Hunger ratings were significantly, albeit moderately, correlated with energy intake (r=0.30) (P<0.05), but not with drinking (r=0.04). On average, 75% of total fluid intake was consumed during periprandial events. Further, energy-yielding beverages were the main contributor to fluid intake during both periprandial and drink-only events. These data fail to reveal associations between either thirst or hunger and ingestion of energy-yielding beverages, or strong associations between hunger and eating or thirst and drinking. These data raise questions about the predictive power of appetitive sensations for ingestive behavior. Article History: Accepted 3 July 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jada.2008.11.031 Byline: Richard D. Mattes, Wayne W. Campbell Abstract: Overweight and obesity have been attributed to increased eating frequency and the size of eating events. This study explored the influence of the timing of eating events and food form on appetite and daily energy intake. Article History: Accepted 25 September 2008

Oral exposure to dietary fat results in an early initial spike, followed by a prolonged elevation, of serum triglycerides in humans. The physiological and pathophysiological implications remain unknown. This study sought to determine the incidence of the effect, the required fat exposure duration, and its reliability. Thirty-four healthy adults participated in four to six response-driven trials held at least a week apart. They reported to the laboratory after an overnight fast, a catheter was placed in an antecubital vein, and a blood sample was obtained. Participants then ingested 50 g of safflower oil in capsules with 500 ml of water within 15 min to mimic a high fat meal but without oral fat exposure. Blood was collected 0, 10, 20, 30, 40, 50, 60, 120, 240, 360, and 480 min after capsule ingestion with different forms (full fat, nonfat, none) and durations of oral fat exposures (10 s, 5 min, 20 min, and/or 2 h). A triglyceride response (increase of triglyceride >10 mg/dl within 30 min) was observed in 88.2%, 70.5%, and 50% of participants with full-fat, nonfat, and no oral exposure, respectively. Test-retest reliability was 75% with full-fat exposure but only 45.4% with nonfat exposure. Full-fat and nonfat exposures led to comparable significant elevations of triglyceride over no oral stimulation with 10-s exposures, but full fat led to a greater rise than nonfat with 20 min of exposure. These data indicate that nutritionally relevant oral fat exposures reliably elevate serum triglyceride concentrations in most people. taste; lipid; cardiovascular disease; chemosensory; cephalic phase

Nuts (ground and tree) are rich sources of multiple nutrients and their consumption is associated with health benefits, including reduced cardiovascular disease risk. This has prompted recommendations to increase their consumption. However, they are also high in fat (albeit largely unsaturated) and are energy dense. The associations between these properties, positive energy balance, and body weight raise questions about such recommendations. This issue is addressed through a review of the literature pertaining to the association between nut consumption and energy balance. Epidemiological studies document an inverse association between the frequency of nut consumption and BMI. Clinical trials reveal little or no weight change with inclusion of various types of nuts in the diet over 1-6 mo. Mechanistic studies indicate this is largely attributable to the high satiety property of nuts, leading to compensatory responses that account for 65-75% of the energy they provide. Limited data suggest chronic consumption is associated with elevated resting energy expenditure resulting in dissipation of another portion of the energy they provide. Additionally, due to poor bioaccessibility, there is limited efficiency of energy absorption from nuts. Collectively, these mechanisms offset much of the energy provided by nuts. The few trials contrasting weight loss through regimens that include or exclude nuts indicate improved compliance and greater weight loss when nuts are permitted. This consistent literature suggests nuts may be included in the diet, in moderation, to enhance palatability and nutrient quality without posing a threat for weight gain.

Ghrelin is reportedly a meal-initiation signal based on observations that concentrations increase before meals coincident with rising hunger. However, evidence that ghrelin peaks vary with feeding schedules suggests that it rises in anticipation of an expected meal, rather than eliciting feeding. To explore the entrainment of ghrelin profiles, this study investigated the association between varying habitual meal patterns and plasma ghrelin concentrations. Lean and obese adults following either a short intermeal interval (SII) pattern, with 2.5-3.5 h between their habitual breakfast and lunch times, or a long intermeal interval (LII) pattern, with 5.5-6.5 h between these eating occasions, participated. Food intake and appetite were recorded for 2 baseline days. On the subsequent test day, blood samples were collected over 8 h while participants ate a breakfast and lunch matched to their customary meals and pattern. Appetite ratings were obtained and ghrelin, insulin, glucose, and leptin concentrations were measured. Peak ghrelin concentrations differed significantly by group and occurred prior to each group's respective lunch time. Ghrelin concentrations directly correlated with subjective hunger. This association was stronger when hunger preceded ghrelin, a pattern inconsistent with ghrelin causing the hunger rise. Ghrelin concentrations were inversely correlated with insulin, and peak insulin concentrations preceded nadir ghrelin concentrations postprandially. Ghrelin concentrations periprandially, and over the entire test session, did not differ by meal group, likely because of similar intakes between groups. These data demonstrate that the timing of ghrelin peaks is related to habitual meal patterns and may rise in anticipation of eating rather than eliciting feeding. hunger; appetite; food intake; satiety; gut hormone

Many older people experience changes in appetite and consume marginal or inadequate dietary protein. This study was designed to examine the appetitive responses to habitual protein intakes that span the range of adequacy in younger and older men. Twenty-two men (12 younger, aged 21-43 y and 10 older, aged 63-79 y) completed, in random order, three 18-d trials that involved consumption of individualized, isoenergetic menus providing 1.00, 0.75, and 0.50 g protein * kg B[W.sup.-1] * [d.sup.-1], which were 125% (trial P125), 94% (trial P94), and 63% (trial P63) of the Recommended Dietary Allowance for protein. Near the end of each trial, the subjects recorded appetitive sensations hourly throughout one day using a visual analogue scale. Independent of age, ratings of hunger were lower for P125 (1.3 [+ or -] 0.5 cm) than P94 (1.8 [+ or -] 0.8 cm)and P63 (1.8 [+ or -] 0.6 cm)(P = 0.037), and desire to eat was lower during the P125 trial (1.4 [+ or -] 0.5 cm), compared with the P63 trial (2.1 [+ or -] 0.7 cm) (P = 0.003), and P94 (1.8 [+ or -] 0.7 cm) was not different when compared with P63 and P125. Protein intake did not influence fullness. These results show that younger and older men who consume inadequate protein experience appetite changes that may promote increased food intake.

Evidence supporting a taste component for dietary fat has prompted study of plausible transduction mechanisms. One hypothesizes that long-chain, unsaturated fatty acids block selected delayed-rectifying potassium channels, resulting in a sensitization of taste receptor cells to stimulation by other taste compounds. This was tested in 17 male and 17 female adult (mean [+ or -] SE age = 23.4 [+ or -] 0.7 yr) propylthiouracil tasters with normal resting triglyceride concentrations (87.3 [+ or -] 5.6 mg/day) and body mass index (23.3 [+ or -] 0.4 kg/[m.sup.2]). Participants were tested during two ~30-min test sessions per week for 8 wk. Eight stimuli were assessed in duplicate via an ascending, three-alternative, forced-choice procedure. Qualities were randomized over weeks. Stimuli were presented as room-temperature, 5-ml portions. They included 1% solutions of linoleic acid with added sodium chloride (salty), sucrose (sweet), citric acid (sour), and caffeine (bitter) as well as solutions of these taste compounds alone. Participants also rated the intensity of the five strongest concentrations using the general labeled magnitude scale. The suprathreshold samples were presented in random order with a rinse between each. Subjects made the ratings self-paced while wearing nose clips. It was hypothesized that taste thresholds would be lower and absolute intensity ratings or slopes of intensity functions would be higher for the stimuli mixed with the linoleic acid. Thresholds were compared by paired t-tests and intensity ratings by repeated measures analysis of variance. Thresholds were significantly higher (i.e., lower sensitivity) for the sodium chloride, citric acid, and caffeine solutions with added fatty acid. Sweet, sour, and salty intensity ratings were lower or unchanged by the addition of a fatty acid. The two highest concentrations of caffeine were rated as weaker in the presence of linoleic acid. These data do not support a mechanism for detecting dietary fats whereby fatty acids sensitize taste receptor cells to stimulation by taste compounds. fatty acid; fat; human; taste transduction; chemosensory doi:10.1152/ajpgi.00510.2006

Selected free fatty acids (FFAs) are documented effective somatosensory and olfactory stimuli whereas gustatory effects are less well established. This study examined orthonasal olfactory, retronasal olfactory, nasal irritancy, oral irritancy, gustatory, and multimodal threshold sensitivity to linoleic, oleic, and stearic acids. Sensitivity to oxidized linoleic acid was also determined. Detection thresholds were obtained using a three-alternative, forced-choice, ascending concentration presentation procedure. Participants included 22 healthy, physically fit adults sensitive to 6-n-propylthiouracil. Measurable thresholds were obtained for all FFAs tested and in 96% of the trials. Ceiling effects were observed in the remaining trials. Greater sensitivity was observed for multimodal stimulation and lower sensitivity for retronasal stimulation. There were no statistically significant correlations for linoleic acid thresholds between different modalities, suggesting that each route of stimulation contributes independently to fat perception. In summary, 18-carbon FFAs of varying saturation are detected by multiple sensory systems in humans. gustatory; olfactory; sensory; multimodal; detection thresholds doi:10.1152/ajpgi.00471.2006

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jada.2006.10.026 Byline: Richard D. Mattes

Humans appear to have a genotype that permits, or even encourages, an energy intake that is greater than energy expenditure when food is available. This was functional throughout most of human evolution but is less so in the current environment of inexpensive, palatable, and readily available foods. To achieve dietary goals of weight loss or maintenance, attempts have been made to influence appetitive sensations through the manipulation of the physical properties of foods, their composition, or their pattern of consumption. This has led to limited success, in part, because measurement of appetitive sensations is difficult but, more fundamentally, because the association between appetite and food choice or intake is not robust. This article critically reviews the most common methods for assessment of appetite and the effects of selected food constituents on appetitive sensations. Translation of current knowledge to dietetic practice must be made cautiously. J Am Diet Assoc. 2005;105:S87-S97.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jada.2005.02.029 Byline: Richard D. Mattes, James Hollis, Dayle Hayes, Albert J. Stunkard Abstract: Humans appear to have a genotype that permits, or even encourages, an energy intake that is greater than energy expenditure when food is available. This was functional throughout most of human evolution but is less so in the current environment of inexpensive, palatable, and readily available foods. To achieve dietary goals of weight loss or maintenance, attempts have been made to influence appetitive sensations through the manipulation of the physical properties of foods, their composition, or their pattern of consumption. This has led to limited success, in part, because measurement of appetitive sensations is difficult but, more fundamentally, because the association between appetite and food choice or intake is not robust. This article critically reviews the most common methods for assessment of appetite and the effects of selected food constituents on appetitive sensations. Translation of current knowledge to dietetic practice must be made cautiously.

Oral exposure to dietary fat (through modified sham feeding, which entails mastication and expectoration of foods) augments the postprandial triacylglycerol (TAG) concentration, in part, though augmented lipid absorption. This study was designed to characterize early events in this process. At 2200 h, 25 healthy adults (13 men, 12 women) consumed 80 g of almonds (high oleic acid content) and fasted until ~0700 h. After placement of a catheter in a hand vein and 4 blood draws at 10-min intervals, 50 1-g safflower oil (high linoleic acid content) capsules were consumed. After another blood draw, modified sham feeding was initiated with a cracker only or cracker with cream cheese in random order with 1 wk between trials. Oral exposures occurred at 5-min intervals for 60 rain then at 15-min intervals from rain 60 to 120. Additional blood draws occurred at 2, 4, 6, 8, 10, 12, 14, 30, 60, 120, 240, 360 and 480 min. Oral stimulation, especially by fat, prompted the rapid (mean ~23 min) release of lipid stored from the previous meal (almonds) in all participants. This resulted in multimodal postprandial triacylglycerol (TAG) peaks generally occurring at 0-30 rain, 60-120 min and 240-480 min after loading and initiation of oral stimulation. TAG magnitudes during these times were correlated (r = 0.40-0.89, P < 0.001-P = 0.053). It is proposed that the sensory-enhanced release of lipid from the residual pool initiates an early TAG rise, which augments the peak attributable to absorption of meal lipid; this in turn supplements a later peak associated with release of endogenously synthesized TAG because lipid from all three sources competed for a common clearance mechanism. If substantiated, additional understanding of the behavioral factors (e.g., eating patterns) that initiate this cascade will be warranted. J. Nutr. 132: 3656-3662, 2002. KEY WORDS: * fat * oral * lipid * taste * humans

R.D. Mattes is a professor of foods and nutrition in the Department of Foods and Nutrition at Purdue University, 212 Stone Hall, West Lafayette, IN 47907-1264; E-mail: mattesr@cfs.purdue.edu, ********** Nutritionally modifiable health disorders in older individuals compromise their quality of life, reduce longevity and burden the health care system and economy. Consequently, there is interest in the determinants [...]

POSITION STATEMENT It is the position of The American Dietetic Association that the fat content of foods may be safely reduced or replaced using approved processing methods and constituents. Individuals [...]

The importance of sensory factors (both the sensory properties of foods and sensory abilities of consumers) in food selection is widely accepted. Less recognized and understood are the effects of sensory stimulation on physiologic processes. Mere exposure to the sight, smell, taste, and textural attributes of foods elicits myriad digestive, endocrinologic, thermogenic, cardiovascular, and renal responses. The responses are rapid (generally occurring within minutes of sensory stimulation), small (relative to the magnitude achieved when food is actually being metabolized), and transient (returning to near-baseline levels within minutes). Nevertheless, they have been hypothesized to prime the body to better absorb and use ingested nutrients. They are termed preabsorptive or cephalic phase responses. This review summarizes current knowledge of stimuli that trigger cephalic phase responses and selected response features (eg, magnitude and type of enzymes or hormones released). Mechanisms by which cephalic phase responses may influence nutrient absorption and use are proposed. Current knowledge of the behavioral and physiologic importance of cephalic phase responses is limited, thereby hampering development of dietary recommendations for preventive or therapeutic interventions. Further study of several identified promising areas of application and other easily proposed situations may provide a basis for expanded medical nutrition therapy. J Am Diet Assoc. 1997; 97:406-410, 413., An influence of the sensory properties of foods on dietary choice is widely recognized. Awareness of sensory influences on the digestion of foods and nutrient use is more limited. However, [...]

Recent advances in knowledge of the basic mechanisms of taste and smell have not been matched by improvements in the clinical management of patients with chemosensory disorders. A principal function [...]

The authors evaluate existing research establishing a causal association between nutritively sweetened beverages (NSBs) and obesity. They stress the need for randomized controlled trials that offer solid, unbiased evidence on the benefits of NSB reduction on obesity and mechanistic studies to explain that evidence.

Oral exposure to dietary fat augments the postprandial triacylglycerol (TAG) concentration. We investigated the TAG response after oral exposure to butter and selected fat replacers. At 2200 h, 17 healthy adults consumed 80 g of almonds and fasted until 0700 h. Safflower oil (50 g in 1-g capsules) was then consumed. Oral stimulation was provided periodically for 2 h as potatoes, potatoes containing butter or one of three fat replacers or no oral stimulation in random order at weekly intervals. Blood was collected at stipulated intervals for 8 h. Oral exposure to butter led to a significantly longer postprandial TAG elevation than the other treatments. The results could not be explained by differential stimulus ingestion, palatability or perceived fat content. There was no significant treatment effect on concentrations of serum oleic acid, apolipoprotein (apo)B-48 or apoB-100, suggesting any oral exposure influence on release of dietary lipid stored in the lacteals or chylomicron and VLDL particle number contributed little to the postprandial TAG rise. In summary, oral exposure to butter elicited a greater postprandial TAG elevation than the tested fat replacers, possibly due to reduced TAG clearance. J. Nutr. 131: 1491-1496, 2001. KEY WORDS: * fat * oral * lipid * taste * humans

Compelling evidence indicates that dietary underreporting is widespread under free-living conditions [1]. Estimates range from 10% to 20% [2,3], although errors up to 50% have been noted in studies of [...]

A fundamental distinction between members of The American Dietetic Association (ADA) and many others who profess to be nutrition experts is the former's steadfast reliance on science-based evidence for all [...]