Diet composition and the metabolic syndrome: what is the optimal fat intake?
Two cholesterol-raising fatty acids in the diet; saturated fatty acids and trans fatty acids; increase the serum low-density lipoprotein cholesterol concentration. This fact justifies the recommendation of a reduced intake of cholesterol-raising fatty acids. Emerging data suggest that diets higher in unsaturated fatty acids; particularly monounsaturated fatty acids; have several advantages over high-carbohydrate intakes. This advantage appears to hold; particularly for populations having a high prevalence of insulin resistance; such as the US population. If the US public were to modify its eating habits in the direction of better weight control and more exercise; higher intakes of carbohydrate might be better tolerated. At the same time; the experience with the Mediterranean population reveals that in healthier populations; diets relatively high in unsaturated fatty acids are well tolerated and are associated with a low prevalence of both coronary heart disease and type 2 diabetes.
Effect on body weight of a free 76 kilojoules (320 calorie) daily supplement of almonds for 6 months.
OBJECTIVE: Regular nut consumption is associated with lower rates of heart attack. However; as nuts are fatty foods; they may in theory lead to weight gain; although preliminary evidence has suggested otherwise. We tested the hypothesis that a free daily supplement (averaging 76 kJ) of almonds for six months; with no dietary advice; would not change body weight. METHODS: Eighty-one male and female subjects completed the randomized cross-over study. During two sequential six-month periods; diet; body weight and habitual exercise were evaluated repeatedly in each subject. Almonds were provided only during the second period. The design was balanced for seasonal and other calendar trends. RESULTS: During the almond feeding period; average body weight increased only 0.40 (kg) (p approximately 0.09). The weight change depended on baseline BMI (p = 0.05); and only those initially in the lower BMI tertiles experienced small and mainly unimportant weight gains with the almonds. We estimated that 54% (recalls) or 78% (diaries) of the extra energy from almonds was displaced by reductions in other foods. The ratio unsaturated/saturated dietary fat increased by 40% to 50% when almonds were included in the diet. CONCLUSION: Incorporating a modest quantity (76 kJ) of almonds in the diet each day for six months did not lead on average to statistically or biologically significant changes in body weight and did increase the consumption of unsaturated fats. Further studies are necessary to evaluate longer term effects; especially in men.
Effects of appetite; BMI; food form and flavor on mastication: almonds as a test food.
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.European Journal of Clinical Nutrition advance online publication; 18 July 2007; doi:10.1038/sj.ejcn.1602838.
Nut consumption; body weight and insulin resistance.
The beneficial effects of nuts on cardiovascular health are well known. However; since nuts provide a high caloric and fat content; some concern exists regarding a potential detrimental effect on body weight and insulin resistance. The current data available did not support such a negative effect of nut consumption on the short term or when nuts are included on diets that meet energy needs. Furthermore; there is some intriguing evidence that nuts can help to regulate body weight and protect against type II diabetes. This; however; still has to be proved and more research is needed to address the specific effects of nuts on satiety; energy balance; body weight and insulin resistance.
Nut consumption and weight gain in a Mediterranean cohort: The SUN study
OBJECTIVE: To assess the association; in a Mediterranean population; between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese. RESEARCH METHODS AND PROCEDURES: The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow-up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food-frequency questionnaire. RESULTS: Nine hundred thirty-seven participants reported a weight gain of > or =5 kg at follow-up. After adjusting for age; sex; smoking; leisure time physical activity; and other known risk factors for obesity; participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90; p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort. DISCUSSION: Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain.
Effects of chronic peanut consumption on energy balance and hedonics
OBJECTIVE: To investigate the effects of chronic peanut consumption on energy balance and hedonics. DESIGN: Thirty-week, cross-over, intervention study. Participants were provided 2113±494 kJ/day (505±118 kcal/day) as peanuts for 8 weeks with no dietary guidance (free feeding—FF), 3 weeks with instructions to add peanuts to their customary diet (addition—ADD) and 8 weeks where peanuts replaced an equal amount of other fats in the diet (substitution—SUB). SUBJECTS: Fifteen, healthy, normal-weight (BMI of 23.3±1.8) adults, aged 33±9 y. MEASUREMENTS: Dietary intake, appetitive indices, energy expenditure, body weight and hedonics. RESULTS: During FF, peanut consumption elicited a strong compensatory dietary response (ie subjects compensated for 66% of the energy provided by the nuts) and body weight gain (1.0 kg) was significantly lower than predicted (3.6 kg; P<0.01). When customary dietary fat was replaced with the energy from peanuts, energy intake, as well as body weight, were maintained precisely. Participants were unaware that body weight was a research focus. Resting energy expenditure was increased by 11% after regular peanut consumption for 19 weeks (P<0.01). Chronic consumption of peanuts did not lead to a decline in pleasantness or hunger ratings for peanuts nor did it lead to any hedonic shift for selected snack foods with other taste qualities during any of the three treatments. CONCLUSIONS: Despite being energy dense, peanuts have a high satiety value and chronic ingestion evokes strong dietary compensation and little change in energy balance.