A comparison of the effect of free access to reduced fat products or their full fat equivalents on food intake, body weight, blood lipids and fat-soluble antioxidants levels and haemostasis variables.

OBJECTIVES: To compare the effects of free access to reduced fat products or their full fat equivalents on fat and energy intake, body weight, plasma lipids and fat-soluble antioxidants concentrations and haemostasis variables. DESIGN: A multicentre open randomised controlled trial in which intervention and control groups were followed in parallel for six months. Volunteers had free access to 44 different foods either in reduced fat or full fat version, covering between 30 and 40% of energy intake. The remainder of energy intake was covered by foods bought in regular shops. SETTING: Zeist, Wageningen and Maastricht, The Netherlands. SUBJECTS: Two hundred and forty-one non-obese healthy volunteers who had no intention to lose weight. MAIN OUTCOME MEASURES: Food intake, body weight, plasma lipid, vitamin E, beta-carotene, lycopene and fibrinogen concentrations, plasma factor VII clotting activity, and plasminogen-activator-inhibitor-I antigen level. RESULTS: One hundred and three volunteers in the full fat group and 117 volunteers in the reduced fat group completed the study. Energy and fat intake from the free access products was lower in the reduced fat group, but no difference in energy and fat intake of other products occurred. Body weight, energy-, fat- and vitamin E intake and percentage of energy derived from fat decreased in the reduced fat group. No other statistical significant intervention effects were observed. Blood lipid concentrations, factor VII activity and plasminogen-inhibitor-activator-1 level were reduced after consumption of reduced fat products. CONCLUSIONS: When subjects without intention to lose weight limit fat intake by switching from ad libitum consumption of full fat products to reduced fat products body weight gain is prevented, and fat and energy intake are reduced. Such a switch may have beneficial effects on biochemical cardiovascular risk factors. We concluded that reduced fat products will help in a population strategy aimed at preventing overweight and obesity, they will also be effective in maintaining a lower body weight after slimming. Ad libitum consumption of reduced fat products will be ineffective for those individuals that want to reduce body weight because they are currently overweight or obese.

A long-term study on the effect of spontaneous consumption of reduced fat products as part of a normal diet on indicators of health.

The growing public concern with the adverse effects on health of a high fat intake has led to a proliferation on the market of reduced fat products. However, no consensus exists on the effectivity of reduced fat products to decrease energy intake. The studies that have investigated this topic have included small numbers of subjects, studied under laboratory conditions and over a relatively short period of time. Therefore, we have executed a long-term study in which volunteers had free access to both reduced fat, commercially available products in the laboratory as well as to products obtained from regular shops. We here report the feasibility of such a type of study and the effects of consumption of reduced fat products on blood levels of cholesterol, haemostasis variables, antioxidants and parameters of the immune system. The study was a multicentre parallel comparison trial of six months (so-called MSFAT-study). 241 volunteers received either reduced fat products or full-fat products and the products were clearly labelled as such. Two months before the start of the study, a 1 month adaptation period was executed to optimize the experimental procedures. Food intake was recorded before the start of the adaptation period and 2-4 weeks, 3 months and 6 months after the start of the study. Blood samples were taken before, after 2, 4 and 6 months of the study. In addition, a selection of the reduced fat and full-fat products was sensorically evaluated three times during the study by a subgroup of the volunteers. 220 volunteers completed the study. The reduced fat group consumed on average 46% less fat from the so-called MSFAT-products obtained from the shop at the laboratory than the control group and consumption of these MSFAT-products did not decrease in either of the groups during the time course of the study. The palatability of the reduced fat and full-fat products was similar and as expected, the perceived fattiness of the full-fat products was higher than that of the reduced fat products. No effects were found on blood levels of cholesterol, haemostasis variables, parameters of antioxidant status and immune system characteristics. In conclusion, the experimental manipulation of the fat content of the diet that was achieved and that remained stable throughout the 6 months of the study indicates that this type of set-up is feasible to assess the effects of long-term nutritional intervention in large groups of volunteers under semi-controlled conditions. The regular use of reduced fat products did not positively but also not adversely affect blood cholesterol levels, antioxidant status, haemostasis factors and the body's immune system.

Energy and fat compensation during long-term consumption of reduced fat products.

The objective of this study was to investigate the behavioral response to the long term realistic consumption of reduced fat products. During six months, a control group of 103 subjects had free access to about 45 commercially available full-fat products, and a reduced-fat group of 117 subjects had access to the reduced fat equivalents. These experimental products covered about 37% of total energy intake in the control group and 30% of energy intake in the reduced fat group. Other non-experimental food products were bought in regular shops. The results showed that, compared to a baseline measurement before the start of the study, energy intake increased from 10.4 MJ/day to 11.2 MJ/d in the control group, whereas it remained constant at 10.2 MJ/d in the reduced fat group. Fat intake in the control group increased from 99 g/d (35.6en%) to 123g/d (40.6en%), whereas fat intake in the reduced fat group decreased from 95 g/d (34.en%) to 90 g/d (32.7en%). The energy and fat intake from experimental products was lower in the reduced fat group (3.1 MJ/d, 37 g fat/d) than in the control group (4.2 MJ/d, 71 g fat/d). There was some compensatory response in the consumption of experimental products: the ingested amount of experimental products was about 10% higher in the reduced fat group (447 g/d) than in the control group (399 g/d)[t = 2.6; p < 0.01]. There was no compensatory response in the consumption of non-experimental products. Both the control and reduced fat group consumed about 7.1 MJ/d and 53 g fat/d from non-experimental products. It is concluded that long term consumption of reduced fat products leads to a lower energy and fat intake, compared to the consumption of full-fat products.

Dietary fat and body fat: an intervention study.

OBJECTIVE: Assessment of body composition in relation to the habitual diet and after a six month dietary intervention. DESIGN: After a baseline measurement subjects were randomly assigned to either a group consuming reduced-fat products or a group consuming full-fat products for six months. SUBJECTS: 108 women and 109 men, equally distributed over the age range 19-35 with BMI between 21 and 28, and the age range 36-55 with BMI between 24 and 30. MEASUREMENTS: Food intake was measured by three day dietary record, body composition by deuterium dilution. RESULTS: At baseline, explained variance of %body fat on age and fat-carbohydrate ratio in the diet together were 17% (P < 0.0001) and 36% (P < 0.0001) for women and men, respectively, and on diet alone 7-8% (P < 0.01) independent of gender. The diet intervention caused on average a change in fat intake and body fat mass in subjects of the reduced-fat group of -5 +/- 29 g/d (P < 0.05) and -0.1 +/- 2.1 kg (ns), respectively, and of +23 +/- 31 g/d (P < 0.0001) and +0.5 +/- 2.3 kg (P < 0.05) in subjects of the full-fat group. The change in the fat content of the diet was positively related to a change in energy intake (fat-carbohydrate ratio: R2 = 0.15, P < 0.0001; g fat: R2 = 0.70, P < 0.0001), the latter explaining 5% of the variation in the change in body fat mass (P < 0.001). Subjects changing the fat content of the diet showed a consequent change in body fat mass only when energy intake changed as well. CONCLUSION: The fat content of the diet has an effect on body fat as a function of the effect of dietary fat on energy intake.

Consumption of reduced-fat products: effects on parameters of anti-oxidative capacity.

OBJECTIVE: Dietary fat intake is higher than recommended in most western countries and is associated with the prevalence of cardiovascular diseases, obesity and cancer. The growing public concern about the adverse effects of a high fat intake has led to an increased availability of ¿reduced-fat' products. Consumption of reduced-fat products might be a convenient way to reduce the energy intake. Besides the potential of reduced-fat products to reduce the energy intake, it might change dietary fat intake, both qualitatively and quantitatively, which in turn might also affect oxidative stress, i.e. the anti-oxidant/pro-oxidant ratio. In this paper we present the effects of 6-month consumption of reduced-fat products on body weight, energy, macronutrient and vitamin E intake, concentration of the plasma lipid peroxidation product malondialdehyde (MDA), erythrocyte free radical scavenging enzymes activities (glutathione peroxidase activity (GSH-Px); superoxide dismutase (SOD) and catalase) as well as plasma fat-soluble anti-oxidative vitamin concentrations (beta-carotene, lycopene and alpha-tocopherol). DESIGN: A randomized semi-controlled parallel comparison trial of six months, preceded by a one-month adaptation period. SETTING: The reduced-fat and full fat products were provided through a realistic shop in order to mimic a ¿free-living' situation. SUBJECTS: Subjects were recruited from respondents on advertisements. Eighty healthy, normal weight (BMI: range 20-30 kg/m2) subjects, aged between 20 and 55y, were selected to participate in this study; 76 subjects completed the study. INTERVENTIONS: 6 months consumption of either reduced-fat or full-fat products. RESULTS: During the intervention period, consumption of reduced fat products resulted in significantly lower energy intake, in a lower percentage of energy derived from saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids as well as in lower vitamin E intake, when compared to the control group. Body weight, the ratio polyunsaturated fatty acids/saturated fatty acids, plasma MDA, vitamin concentrations (beta-carotene, lycopene and alpha-tocopherol), and erythrocyte free radical scavenging enzyme activities (SOD, GSH-Px and catalase) were not affected by the intervention. CONCLUSION: Neither the difference in energy intake, nor the change in dietary fat composition seems to affect the integrity of the antioxidant scavenging capacity, assessed by measuring plasma MDA and antioxidative vitamins (lycopene, beta-carotene and alpha-tocopherol) and erythrocyte free radical scavenging enzymes (SOD, GSH-Px and catalase).

Beneficial effect of a moderately energy-restricted diet on fibrinolytic factors in non-obese men.

Impaired fibrinolytic activity has been reported in the elderly and is thought to play a role in the etiology of cardiovascular disease, one of the leading causes of death in most Western countries. Since restriction of energy intake has been demonstrated to act beneficially on the aging process in a variety of species, we studied the effect of a 10-week moderately energy-restricted (ER) regimen (80% of habitual) on plasminogen activator inhibitor (PAI) activity, PAI-1 antigen, tissue plasminogen activator (tPA) activity, and tPA antigen in non-obese, middle-aged men. Moreover, the relationship between these fibrinolytic markers and glucose tolerance was investigated. Weight loss in the ER group (n = 16) was considerable (-7.4 +/- 1.7 kg, P < .001). Subjects in the control group (n = 8) also lost some weight (-2.1 +/- 1.5 kg, P < .01). Fasting glucose levels decreased in the ER group (-0.31 +/- 0.48 mmol/L, P < .05), which was correlated with the extent of weight loss (P < .01). Baseline insulin levels at 2 hours after an oral glucose load correlated with baseline PAI activity (P < .001) and PAI-1 antigen levels (P < .001). PAI activity decreased in the ER group (-2.94 +/- 2.90 IU/mL, P < .001), particularly in subjects with a high baseline PAI activity (> 9 IU/mL). Furthermore, energy restriction led to decreased PAI-1 antigen concentration (P < .05), a nonsignificant increase in tPA activity, and a decrease in tPA antigen concentration (P < .001). All these changes were more clear in subjects with a high baseline PAI activity. These results suggest that 10 weeks of moderate energy- restriction has a profibrinolytic effect in non-obese, middle-aged men, at least in subjects with higher baseline PAI activity (> 9 IU/mL). Moreover, in line with the suggestion that high PAI activity goes together with insulin resistance, a relationship between insulin concentration after a glucose load and PAI activity was found.

Short-term moderate energy restriction does not affect indicators of oxidative stress and genotoxicity in humans.

Restriction of energy intake (ER), without malnutrition of essential nutrients, has repeatedly been demonstrated to increase longevity in rodents. In the antioxidant theory of aging the lack of balance between the generation of free radicals and free radical scavenging was thought to be a main causal agent, in the aging process. From this point of view the antiaging effect induced by ER might be due to the lower rate of free-radical production and related damage induced by a lower metabolic rate. The antiaging effects of ER might also occur in humans. This study explored the effects of a 10-week moderately energy-restricted diet (80% of habitual) in 24 non-obese middle-aged men (16 ER subjects, 8 controls) on resting metabolic rate (RMR) and indicators of the primary antioxidant defense system, oxidative stress and genotoxicity. RMR decreased significantly in both groups, even when adjustments were made for the change in body composition. The increase in blood vitamin C concentration correlated with the increase in urinary 8-hydroxydeoxyguanosine (80HdG) excretion. The change in urinary 80HdG excretion also correlated with the change in RMR per kg fat-free mass. No differences between groups were found for changes in indicators of genotoxicity, erythrocyte catalase, glutathione peroxidase and superoxide dismutase activity and in plasma vitamin E, A or beta-carotene concentrations. We conclude that 10 weeks of moderate ER did not affect indicators of antioxidative capacity, oxidative stress and genotoxicity of humans. Since subjects were not in energy balance at the end of the study, no conclusions can be made with respect to long-term effects.

Energy restriction and oxidative DNA damage in humans.

The cancer-preventive effect of energy restriction in rodents has been related to a decrease in oxidative damage to DNA. We have investigated the effect of energy restriction on the rate of oxidative DNA modification estimated from the urinary excretion of the repair product, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), in healthy, normal weight men. Before and after 10 weeks on a diet containing 80 (n = 16) or 100% (n = 8) of the estimated weight-maintaining energy, resting metabolic rate (RMR) was measured and 24-h urine was collected for 8-oxodG determination by HPLC. During the study, the weight loss was 10 and 2.5% of the initial weight, mostly in terms of fat, and the RMR decreased by 13 and 8% in the energy-restricted and control groups, respectively. With the use of t tests there was no significant difference within or between groups with respect to 8-oxodG excretion. However, if RMR was included as a covariate in multifactorial ANOVA, an average relative 17% (2-31%; 95% confidence interval) increase in 8-oxodG excretion in the energy-restricted group was significantly different from the corresponding value of the control group (P < 0.02). In the energy-restricted group the change in 8-oxodG excretion was correlated closely with the decrease in RMR (r = 0.63; P = 0.013). In the present study, 20% energy restriction for 10 weeks did not reduce oxidative DNA damage; we question a beneficial effect on cancer risk in normal weight humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of a moderately energy-restricted diet on energy metabolism and body composition in non-obese men.

OBJECTIVE: Since little information is available on the capacity of the non-obese to adapt to a moderate decrease in energy intake, the effect of a 10-week moderately energy-restricted diet (ER) on energy expenditure and body composition was studied. DESIGN: A controlled intervention study. After a weight-maintaining run-in period of 2 weeks, the ER group received a diet that contained 9.2 MJ/day on average, i.e. 80% of the energy of their habitual diet (estimated by means of a 7-day dietary record) for the next ten weeks while the control group received the weight-maintaining diet. SETTING: Subjects continued daily life habits and came to the Institute every evening to have dinner and to receive food for the next 24 h. SUBJECTS: 24 healthy non-obese, middle-aged men participated. Subjects were matched for age and body mass index and randomly assigned to a control group (n = 8) or an ER group (n = 16). RESULTS: Average daily metabolic rate (ADMR, i.e. total energy expenditure), measured with doubly labeled water in eight subjects of the ER group, appeared to be 82.5% of reported energy intake resulting in an actual level of energy restriction in these eight subjects of 33% on average (range 18-42%), rather than 20%. Subjects in the ER group lost 7.4 +/- 1.7 kg; 83% of this weight loss was fat mass, 17% was fat-free mass. Subjects in the control group lost some weight too (2.1 +/- 1.5 kg). Resting metabolic rate (RMR) (MJ/day) decreased in the ER group (P < 0.001). In this group the thyroid hormone triiodothyronine (T3) decreased (P < 0.001), while reverse T3 (rT3) increased (P < 0.05). ADMR decreased significantly. CONCLUSION: Under conditions of a controlled moderately energy-restricted diet in daily life a significant weight loss can be induced, similar to that observed after a balanced dietary deficit, providing 5 MJ/day. In addition, moderate energy restriction induces a decrease in fat-free mass and a fall in RMR.

Effects of moderate energy restriction on physical performance and substrate utilization in non-obese men.

Energy restriction (ER) has shown to be an effective 'anti-aging' factor in rodents, resulting in an increased life span and preventing or delaying the occurrence of many age-related diseases in rodents. As a part of a feasibility study on the potential application of ER in humans, we studied the effects of moderate ER on physical performance in 24 apparently healthy, non-obese middle-aged men. After two weeks of weight maintenance the ER group (n = 16) received 80% of their habitual energy intake, while a control group (n = 8) still received their weight-maintaining diet for ten weeks. Physical performance (bicycle ergometer) was estimated by a maximal (until exhaustion) and a submaximal (30 min at 60% of VO2max) exercise test. After the experimental period the subjects in ER group had a significantly shorter cycling time (delta = 1.31 +/- 1.14 vs -0.45 +/- 1.56 min, p = 0.01), and thus had a lower maximal power output (delta = 4.3 +/- 5.9 vs -6.3 +/- 13.6 watt, p < 0.05) and maximal oxygen uptake (delta = 0.03 +/- 0.18 vs -0.18 +/- 0.321/min, p = 0.05) during the maximal exercise test, than the subjects in the control group. None of these changes correlated with weight loss. As in every exercise test, motivation could have played an important role. During the submaximal exercise test no significant changes between the two groups in HR, VO2, RER and FFA, glucose, lactate and catecholamine levels were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of moderate dose of alcohol with evening meal on fibrinolytic factors.

OBJECTIVES: To evaluate the effects of moderate consumption of alcoholic beverages on the fibrinolytic system and to assess whether these effects could help explain the relation between moderate alcohol consumption and reduced coronary heart disease. DESIGN: Four treatments were allocated in a randomised controlled order on four days over a period of 11 days. SETTING: Metabolic ward of research institute. SUBJECTS: Eight white healthy middle aged men. INTERVENTIONS: Subjects were provided with food for the 11 days. On the four study days mineral water or 40 g of alcohol in the form of beer, wine, or spirits was consumed at dinner early in the evening. MAIN OUTCOME MEASURES: Plasminogen activator inhibitor activity, tissue type plasminogen activator antigen, and tissue type plasminogen activator activity one hour before and one, three, five, nine, and 13 hours after dinner with mineral water or alcoholic beverages. RESULTS: After dinner with alcohol plasminogen activator inhibitor activity rose from 53 (SD 19)% to a maximum of 667 (283%) five hours after dinner (P < 0.001). Tissue type plasminogen activator antigen levels rose from 5.3 (2.2) micrograms/l to a maximum of 10.8 (3.8) micrograms/l nine hours after dinner with alcohol (P < 0.001). Plasminogen activator activity was reduced in the postprandial period (from 1387 (483) IU/l to 323 (288) IU/l five hours after eating; P < 0.001) but was higher than normal early the next morning (1516 (809) IU/l after alcohol, 779 (516) IU/l after water; P = 0.04). CONCLUSION: Moderate alcohol consumption with dinner affects plasminogen activator inhibitor activity, plasminogen activator antigen level, and tissue type plasminogen activator activity temporarily. The effects observed in the early morning are consistent with a decrease in risk of coronary heart disease in moderate drinkers.

Between-laboratory comparison of densitometry and bio-electrical impedance measurements.

Body composition was measured in nine healthy, normal-weight, weight-stable subjects in three different research centres. In each centre the usual procedures for the measurements were followed. It revealed that the measurement procedures in the three centres were comparable. Body composition was measured in each centre between 09.00 and 13.00 hours after a light breakfast by densitometry (underwater weighing) and bio-electrical impedance. A single, total-body-water determination by D2O dilution was used as a reference value. Body fat determined by densitometry was significantly lower in one centre, which, however, could be completely explained by a lower body weight, probably due to water loss (the subjects refrained for a longer time from food and drinks before the measurements in that centre) and, thus, by violation of the assumptions of Siri's (1961) formula. Also, body impedance was slightly higher in that centre, indicating a lower amount of body water. Mean body fat from densitometry was also slightly lower in that centre compared with body fat determined by D2O dilution. Individual differences between body fat from densitometry and from total body water were relatively large, up to 7% body fat. The relationship between fat-free mass from densitometry and bio-electrical impedance was not different between the centres. It is concluded that differences in the relationship between body composition and bio-electrical impedance, as reported in the literature, may be due to differences in standardization procedures and/or differences in reference population.

Energy restriction, a useful intervention to retard human ageing? Results of a feasibility study.

OBJECTIVE: Energy restriction (ER) retards the ageing process in animal models. It is possible that ER has a similar effect in humans. As a first approach to look after the potential application of ER in man the feasibility of a moderately energy-restricted diet was studied. DESIGN: A controlled intervention study. SETTING: TNO Toxicology and Nutrition Institute. SUBJECTS: 24 middle-aged non-obese men, selected from men responding to advertisements in regional newspapers. INTERVENTIONS: After a run-in period subjects were divided into two groups, a control group (n = 8) and an ER group (n = 16). Groups were matched on age and body mass index. The effects of 10 weeks of moderate ER (80% of habitual energy intake) on body composition, general health (blood pressure, lipid profile, routine clinical chemistry and haematology), physical and mental performance, and feelings of hunger, satiety and state of mind were measured. RESULTS: Subjects in the ER group lost about 7.4 +/- 2.6 kg weight (P < 0.001). This weight loss concerned mainly loss of fat mass. Diastolic and systolic blood pressure decreased significantly within the ER group (P < 0.05 and P < 0.01 respectively). The increase in HDL-cholesterol level was significantly related to weight loss (P < 0.05). CONCLUSIONS: The results show beneficial effects of 10 weeks of moderate ER on blood pressure and lipid profile without adverse effects on physical and mental performance and feelings of hunger, satiety and mood.