Frecka, J.M., J.H. Hollis, R.D. Mattes, 2008. Effects of appetite, BMI, food form and flavor on mastication: almonds as a test food. Eur J Clin Nutr. 62, 1231-1238.
Objectives: To investigate the effects of appetitive sensations, body mass index (BMI) and physical/sensory properties of food (almonds) on masticatory indices and resultant pre-swallowing particle sizes. Subjects/Methods: Twelve lean (BMI=22.2±0.3) and 12 obese (BMI=34.3±0.6) adults. After collecting appetitive ratings, electromyographic recordings were used to assess participants’ microstructure of eating for five almond products (raw, dry unsalted roasted, natural sliced, roasted salted and honey roasted) under fasted and satiated conditions. Duplicate samples were masticated to the point of deglutition and then were expectorated and size sorted. Results: No statistically significant effects of BMI were detected for any of the mastication measures. Maximum and mean bite forces were greater under the fasted condition. Sliced almonds required lower bite force than did the other almond varieties. The pre-swallowing particle sizes were significantly greater for the sliced almonds than all other varieties. Both the number of chews and mastication time were negatively correlated with particle size. There were no significant effects of almond form or flavor on particle size. Conclusions: These results do not support differences in masticatory performance between lean and obese individuals, nor effects of sensory properties. Instead, the physical form of foods as well as an individuals’ appetitive state may have a greater influence on masticatory behavior. The health implications of these observations warrant further investigation.
Mattes, R.D., P.M. Kris-Etherton, G.D. Foster, 2008. Impact of peanuts and tree nuts on body weight and healthy weight loss in adults. J. Nutr. 138: 1741S-1745S.
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.
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Natoli, S., P. McCoy, 2007. A review of the evidence: nuts and body weight. Asia Pac J Clin Nutr. 16 (4):588-597 588.
There is currently no single dietary or lifestyle intervention that is effective in long-term weight loss. Traditional weight loss diets tend to be low in total fat and therefore often restrict nut consumption. However, nuts are an important source of many vitamins, minerals, monounsaturated and polyunsaturated fatty acids. This paper reviewed all the available evidence from the literature in relation to nut consumption and body weight. The findings show that the role of nut consumption in body weight management is varied. Nuts, when included as part of an energy-controlled diet, were found in some instances to assist with weight loss. However, when nuts were added to an existing diet without controlling for energy intake, body weight increased, although to a lesser extent than theoretically predicted. There is limited evidence on the effect nut consumption has on type 2 diabetes, although available evidence indicates that nuts as part of a healthy diet do not cause weight gain and can have a positive influence on the fatty acid profile of a person with diabetes. This review shows there is a lack of evidence to support the restriction of nut consumption in weight management, indicating that further research is needed to assess the role of nuts in weight management.
Hollis, J., R. Mattes, 2007. Effect of chronic consumption of almonds on body weight in healthy humans. Brit. J. Nutr. 98:651-656.
Small changes of diet may reduce CVD risk. One example is the inclusion of nuts, which are rich in fiber, unsaturated fatty acids and phytonutrients. However, their fat content and energy density raise concerns that chronic consumption will promote weight gain. Randomized intervention studies are required to evaluate whether this concern is well founded. This study’s aim was to determine if the inclusion of a 1440 kJ serving of almonds in the daily diet results in positive energy balance, and body composition change. During a 23-week cross-over design study, participants were required to consume almonds for 10 weeks and were provided no advice on how to include them in their diet. For another 10 weeks (order counter-balanced), participants followed their customary diet and there was a 3-week washout between. A study group of twenty women was used. Potential mechanisms of energy dissipation were measured. Ten weeks of daily almond consumption did not cause a change in body weight. This was predominantly due to compensation for the energy contained in the almonds through reduced food intake from other sources. Moreover, inefficiency in the absorption of energy from almonds was documented (P<0.05). No changes in resting metabolic rate, thermic effect of food or total energy expenditure were noted. A daily 1440 kJ serving of almonds, sufficient to provide beneficial effects on cardiovascular risk factors, may be included in the diet with limited risk of weight gain. Whether this can be generalized to other high-fat energy dense foods warrants evaluation.
Jebb, S.A., 2007. Dietary determinants of obesity. Obesity Reviews.8 (Suppl. 1)93-97
One of the few incontrovertible facts about obesity is that weight is only gained when energy intake exceeds energy needs for a prolonged period. This is clear from studies of basic physiology under standardized conditions and controlled intervention studies involving manipulations of the components of energy balance. However, energy intake must be considered in the context of an individual’s energy needs. Obesity results not from a high absolute energy intake but from intake which exceeds energy needs, even as a small fraction of energy flux. It is thus the coupling between intake and expenditure that lies at the heart of the problem. The search for specific dietary factors that increase the risk of obesity is therefore a quest for factors that undermine the innate regulatory control of body weight. There are multiple mechanisms by which this can occur which are explored elsewhere in this series of reviews, including satiety, palatability, food availability or low-energy needs as a consequence of physical inactivity. This review will focus on the evidence for specific dietary determinants of obesity largely from observational and intervention studies.
Rajaram, S., J. Sabate’, 2006. Nuts, body weight and insulin resistance. British Journal of Nutrition. 96, Suppl. 2, S79-S86.
Traditionally, nuts have been considered a staple food, but because of their high energy and fat content are not considered good for body weight control or insulin sensitivity. Frequent consumption of nuts reduces the risk of coronary artery disease and type-2 diabetes and nut-enriched diets favorably alter blood lipids in normal and hypercholesterolemic individuals under controlled and free-living dietary conditions. However, whether or not frequent consumption of nuts can cause weight gain and impair insulin sensitivity is not fully understood. Review of the available data to date suggests that adding nuts to habitual diets of free-living individuals does not cause weight gain. In fact, nuts have a tendency to lower body weight and fat mass. In the context of calorie-restricted diets, adding nuts produces a more lasting and greater magnitude of weight loss among obese subjects while improving insulin sensitivity. Further studies are needed to clarify the effect of long-term ($ year) consumption of nuts on body weight and their role in altering insulin sensitivity both in normal and type-2 diabetics. In the meantime, there is sufficient evidence to promote the inclusion of nuts as part of healthy diets.
St-Onge, M.P., 2005. Dietary fats, teas, dairy, and nuts: potential functional foods for weight control? Am J Clin Nutr. 81:7-15.
Functional foods are similar to conventional foods in appearance, but they have benefits that extend beyond their basic nutritional properties. For example, functional foods have been studied for the prevention of osteoporosis, cancer, and cardiovascular disease. They have yet to be related to the prevention of obesity, although obesity is one of the major health problems today. The inclusion of foods or the replacement of habitual foods with others that may enhance energy expenditure (EE) or improve satiety may be a practical way to maintain a stable body weight or assist in achieving weight loss; such foods may act as functional foods in body weight control. Some foods that might be classified as functional foods for weight control because of their effects on EE and appetite—including medium chain triacylglycerols, diacylglycerols, tea, milk, and nuts—are reviewed here. Only human studies reporting EE, appetite, or body weight are discussed. When studies of whole food items are unavailable, studies of nutraceuticals, the capsular equivalents of functional foods, are reviewed. To date, dietary fats seem to be most promising and have been the most extensively studied for their effects on body weight control. However, the weight loss observed is small and should be considered mostly as a measure to prevent weight gain. Carefully conducted clinical studies are needed to firmly ascertain the effect of tea, milk, and nuts on body weight maintenance, to assess their potential to assist in weight-loss efforts, and to ascertain dose-response relations and mechanisms of action for the 4 food types examined.
Sabate, J., Z. Cordero-MacIntyre, G. Siapco, S. Torabian, E. Haddad, 2005. Does regular walnut consumption lead to weight gain? Brit J Nutr. 94(5):859-64.
Studies consistently show the beneficial effects of eating nuts, but as high-energy foods, their regular consumption may lead to weight gain. We tested if daily consumption of walnuts (approximately 12% energy intake) for 6 months would modify body weight and body composition in free-living subjects. Ninety participants in a 12-month randomized cross-over trial were instructed to eat an allotted amount of walnuts (28-56 g) during the walnut-supplemented diet and not to eat them during the control diet, with no further instruction. Subjects were unaware that body weight was the main outcome. Dietary compliance was about 95% and mean daily walnut consumption was 35 g during the walnut-supplemented diet. The walnut-supplemented diet resulted in greater daily energy intake (557 kJ (133 kcal)), which should theoretically have led to a weight gain of 3.1 kg over the 6-month period. For all participants, walnut supplementation increased weight (0.4 (SE 0.1) kg), BMI (0.2 (SE 0.1) kg/m2), fat mass (0.2 (SE 0.1) kg) and lean mass (0.2 (SE 0.1) kg). But, after adjusting for energy differences between the control and walnut-supplemented diets, no significant differences were observed in body weight or body composition parameters, except for BMI (0.1 (SE 0.1) kg/m2). The weight gain from incorporating walnuts into the diet (control → walnut sequence) was less than the weight loss from withdrawing walnuts from the diet (walnut → control sequence). Our findings show that regular walnut intake resulted in weight gain much lower than expected and which became non-significant after controlling for differences in energy intak
Jaceldo-Siegl, K., J. Sabate, S. Rajaram, G.E. Fraser, 2004. Long-term supplementation without advice on food replacement induces favourable nutrient modifications to the habitual diets of free-living individuals. Brit. J. Nutr. 92:533-540.
Epidemiological and metabolic studies have shown that regular nut consumption may protect against risk of heart disease and diabetes. None has investigated the effect of adding nuts to a self-selected habitual diet (containing little or no nuts) on dietary patterns. The present study evaluated the impact of long-term almond supplementation in healthy men (n 43) and women (n 38) aged 25–70 years on nutrient profile and nutrient displacement. All subjects were followed for 1 year. During the first 6 months, subjects followed their habitual diets; in the second 6 months, subjects added almonds to their diets. Diets were assessed by seven random 24 h telephone diet recalls during each diet period. On average, the almond supplement was 52 g/d (about forty-two nuts) containing 1286 kJ. When subjects changed from their habitual diet to the almond-supplemented diet, the intakes of MUFA, PUFA, fiber, vegetable protein, α-tocopherol, Cu and Mg significantly (P<0.05) increased by 42, 24, 12, 19, 66, 15 and 23% respectively; the intakes of trans fatty acids, animal protein, Na, cholesterol and sugars significantly (P<0.05) decreased by 14, 9, 21, 17 and 13% respectively. These spontaneous nutrient changes closely match the dietary recommendations to prevent cardiovascular and other chronic diseases. Displacement estimates for total energy, total protein, total fat, SFA, MUFA, PUFA, total fiber, Ca, Fe, Mg, P, K, Zn and α-tocopherol ranged from 16 to 98%; the estimates for total food weight, carbohydrate, sugars and Se were >245 %. A daily supplement of almonds can induce favorable nutrient modifications for chronic disease prevention to an individual’s habitual diet.
Burton-Freeman, B., P.A. Davis, B.O. Schneeman, 2004. Interaction of fat availability and sex on postprandial satiety and cholecystokinin after mixed-food meals. Am. J. Clin. Nutr. 80:1207-14.
Background: Cholecystokinin (CCK) is associated with fat induced satiety. Objective: The primary objective of the present study was to determine, in an acute meal setting, whether the availability of dietary fat for alimentary processing, and hence the stimulation of CCK, affects the postmeal satiety response in men and women. Design: In a within-subjects design, subjects (8 men, 7 women) consumed 1 of 3 isoenergetic mixed-food test meals 1 wk apart in random order. The test meals contained 30% of energy from fat, of which more than two-thirds was derived from whole almonds, almond oil, or a mix of safflower and corn oils. Visual analogue scales were used to assess indexes of satiety at defined time points up to 6 h after meal consumption. Blood was sampled at corresponding time points for measurement of CCK, glucose, insulin, and triacylglycerol. Subsequent food intake was also assessed. Results: All meals suppressed hunger and induced a pattern of satiety that was sex-specific and corresponded with the CCK response. Women had higher plasma CCK concentrations and experienced greater satiety after the almond oil and control meals (fat as oil) than after the whole almond meal (fat in whole food structure). Men showed no differential response among meals for CCK and satiety. Plasma triacylglycerol differed by time among meals but not by sex, and no significant differences in glucose and insulin were found. Conclusions: The satiety response to dietary fat provided in oil or whole food form is influenced by sex and is dependent on the availability of fat to stimulate CCK release in women but not in men.
