Scientific Opinion on the substantiation of health claims related to
very low calorie diets (VLCDs) and reduction in body weight (ID 1410),
reduction in the sense of hunger (ID 1411), reduction in body fat mass
while maintaining lean body mass (ID 1412), reduction of post-prandial
glycaemic responses (ID 1414), and maintenance of normal blood lipid
profile (ID 1421) pursuant to Article 13(1) of Regulation (EC) No 1924/2006[sup]1[/sup]
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3
European Food Safety Authority (EFSA), Parma, Italy
Słowa kluczowe:
VLCD
Very low calorie diets
body fat mass
health claims
hunger
lean body mass
lipid profile
post-prandial glycaemic response
weight loss
1. Charakterystyka żywności / składnika
The diet that is the subject of the claims is "very low calorie diet (VLCD) program".
Very low calorie diets (VLCDs) or very low energy diets are diets which contain energy levels between 450 and 800 kcal per day, and 100 % of the recommended daily intakes for vitamins and minerals. They should contain not less than 50 g of high-quality protein (protein-digestibility-corrected amino acid score of 1), should provide not less than 3 g of linoleic acid and not less than 0.5 g alpha-linolenic acid with a linoleic acid/alpha-linolenic acid ratio between 5 and 15, and should provide not less than 50 g of available carbohydrates (CODEX STAN 203-19956). VLCDs are typically used for 8-16 weeks.
The Panel notes that the nutritional composition and use of VLCDs is not regulated in the European Union.
Additional components or interventions included in a "very low calorie diet (VLCD) program", however, are not sufficiently characterised; these may vary between programs and may affect both initial weight loss and long term weight maintenance. Similarly, the types of available carbohydrates (e.g. their chemical composition and physical properties) which formula foods for use in VLCDs should contain, are not specified. The Panel also notes that the fatty acid composition of formula foods for use in VLCDs is only partially specified (CODEX STAN 203-1995).
The Panel considers that whereas the diet which is the subject of the claim, VLCD, is sufficiently characterised in relation to the following claimed effects: reduction in body weight (ID 1410), reduction in the sense of hunger (ID 1411), and reduction in body fat mass while maintaining lean body mass (ID 1412), VLCD is not sufficiently characterised in relation to: reduction of post-prandial glycaemic responses (ID 1414) and maintenance of normal blood lipid profile (ID 1421), mainly owing to the lack of standardisation of the type of available carbohydrates and of most of the fatty acids that formula foods for use in VLCDs should contain.
The Panel concludes that a cause and effect relationship cannot be established between the consumption of a VLCD and reduction of post-prandial glycaemic responses (ID 1414) and maintenance of normal blood lipid profile (ID 1421).
The Panel considers that the diet which is the subject of the claim, VLCD, is sufficiently characterised in relation to the following claimed effects: reduction in body weight (ID 1410), reduction in the sense of hunger (ID 1411) and reduction in body fat mass while maintaining lean body mass (ID 1412).
2. Znaczenie oświadczenia dla zdrowia człowieka
2.1. Redukcja masy ciała (ID 1410)
The claimed effect is “safe and effective weight loss, long term weight maintenance”. The Panel assumes that the target population is obese adults who wish to reduce their body weight.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers to a reduction in body weight.
Weight loss can be interpreted as the achievement of a normal body weight in previously obese subjects. In this context, weight loss in obese subjects without the achievement of a normal body weight is considered a beneficial physiological effect.
The Panel considers that reduction in body weight is a beneficial physiological effect.
2.2. Redukcja odczuwania uczucia głodu (ID 1411)
The claimed effect is “reduced hunger”. The Panel assumes that the target population is obese adults in the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers to a reduction in sense of hunger mediated by the induction of ketogenesis during a sustained energy deficit.
The Panel considers that reduction in the sense of hunger during a sustained energy deficit is a beneficial physiological effect.
2.3. Redukcja tkanki tłuszczowej z utrzymaniem beztłuszczowej masy ciała (ID 1412)
The claimed effect is “burning fat for energy, preserving lean tissue”. The Panel assumes that the target population is obese adults in the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers to the loss of fat mass while maintaining lean body mass during weight loss.
The Panel considers that reduction in body fat mass while maintaining lean body mass is a beneficial physiological effect.
2.4. Zmniejszenie stężenia glukozy we krwi po posiłku (ID 1414)
null
2.5. Utrzymanie prawidłowego profilu lipidów we krwi (ID 1421)
null
3. Naukowe uzasadnienia wpływu na zdrowie człowieka -
3.1. Redukcja masy ciała (ID 1410)
The references provided for the scientific substantiation of the claim included abstracts with insufficient information for a scientific evaluation, narrative reviews, and human intervention studies on diets other than VLCDs (e.g. low carbohydrate diets and low fat diets) and/or effects other than body weight changes (e.g. body composition and snoring). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
Four reviews (Ayyad and Andersen, 2000; Jebb and Goldberg, 1998; Miura et al., 1989; Mustajoki and Pekkarinen, 2001) and two meta-analyses (Anderson et al., 2004; Gilden Tsai and Wadden, 2006) including most of the original human intervention studies presented on the effects of VLCDs on body weight loss were provided.
The two meta-analyses were based on 19 individual studies including more than 2,500 overweight or obese subjects (the majority of whom were obese) of both sexes (the majority of whom were females) treated with VLCDs for between eight and 28 weeks (median 22 weeks), and with a follow-up period of between one and five years.
The meta-analysis by Anderson et al. (2004) was based on 47 intervention studies conducted in obese but otherwise healthy adult subjects (BMI at least 30 kg/m2 at baseline) which assessed the effects of meal replacements (at least two meal replacements per day, four studies), energy restricted diets (providing >1,500 kcal per day, six studies), low-energy diets (providing 800-1500 kcal per day, 10 studies), VLCDs (providing up to 800 kcal per day, 19 studies), and soy diets (providing up to 800 kcal per day, eight studies), and reported weight loss data after 24 weeks of treatment. Participants in the 19 studies on VLCDs were 1,968 obese subjects of both sexes with an average initial BMI of 39.6 kg/m2 (range 36.1 to 41.9 kg/m2). The mean drop-out rate in these studies was 35.3 %. Data were reported for 1,347 women and 396 men. Subjects lost an average of 22.6 % of their initial body weight over the 24 weeks of intervention; such weight loss was significantly higher than the weight loss achieved with any other weight loss strategy considered, and this significant difference with respect to other weight loss strategies was maintained after one year. However, no significant differences in body weight loss were observed between weight loss strategies at longer follow-ups. Subjects on VLCDs maintained an average weight loss of 16.1 %, 9.7 %, 7.8 %, 7.0 % and 6.2 % of their initial body weight at follow-up after one, two, three, four and five years, respectively. Large individual differences were observed in long-term effectiveness depending on the initial amount of weight loss, additional (behavioural) interventions, and level of physical activity. VLCDs and low-energy-diet programs were the weight loss strategies which required more aggregated medical visits, clinic visits and class hours (e.g. intensity score about four times higher than meal replacements). The Panel notes that the majority of studies presented data on completers only, and not on the intention-to-treat population.
The meta-analysis by Gilden Tsai and Wadden (2006) included only randomised controlled trials (RCTs) comparing the efficacy of low calorie diets (LCDs) vs. VLCDs, and which included follow-up data of at least one year after maximum weight loss. Six RCTs including 233 subjects met the inclusion criteria. Initial VLCD treatment for 8-12 weeks followed by an LCD containing 1,000 to 1,600 kcal/day and behavioural treatment for additional 12 to 104 weeks was compared to LCD and behavioural treatment of similar durations. Maximal weight loss for subjects in the VLCD group ranged between 13.4 and 19.9 % of initial body weight, which was approximately 6.5 % more than that observed for subjects in the LCD group. Body weight at 1.5-2 years of follow-up in the VLCD group was -12.3 to -7.6 % of initial body weight, which was slightly but still significantly (1.5 % difference) lower than in the LCD group.
The remaining references and reviews, which addressed the effects of VLCDs on weight loss compared to other dietary strategies aimed at weight loss, are in agreement with these two meta-analyses. Compared with other non-surgical interventions for weight loss, VLCDs in the context of intense supervision (e.g. by physicians and other health professionals) lead to greater weight loss (ranging from 12 to 20 % of initial body weight or about 12 to 35 kg) after 8-16 weeks of treatment, although considerable weight regain occurs when follow-up is extended for a number of years, particularly in the absence of behavioural modifications at follow-up. However, about one third of women and about 28 % of men still had 10 % lower body weight after five years. Those subjects had generally been more successful during the weight loss phase (Jebb and Goldberg, 1998; Mustajoki and Pekkarinen, 2001; Pekkarinen et al., 1996).
Although VLCDs appear to be superior in producing large initial weight loss compared with other dietary interventions, long-term success is highly dependent on additional interventions including long-term life-style changes and active follow-up (Ayyad and Andersen, 2000). Miura et al. (1989) assessed the effects of combining VLCDs and behavioural modifications vs. the effects of either VLCD alone or behavioural modification alone in 70 obese subjects refractory to other weight loss interventions. VLCD alone or in combination with behavioural modifications showed no significant
differences in initial weight loss (7.5 2.1 vs. 8.3 2.3 kg/month). However, after 2 years, the group on
VLCD only had regained on average 4.3 3.5 kg (>50% of their initial weight loss) while the group receiving the combination of VLCD plus behavioural modification had lost one additional kg
(-1.0 0.7 kg) and the group on behavioural therapy only had lost an additional 1.3 2.2 kg. Compared to the group receiving behavioural therapy only, the total weight loss at two years was not significantly different in the group on VLCD only (approximately -5 kg in both groups).
In weighing the evidence, the Panel took into account that the evidence provided consistently showed a greater reduction of body weight in obese subjects on VLCDs compared to other dietary interventions aimed at weight loss.
The Panel concludes that a cause and effect relationship has been established between the consumption of a VLCD and reduction in body weight.
3.2. Redukcja odczuwania uczucia głodu (ID 1411)
The references provided for the scientific substantiation of the claim included narrative reviews, and human intervention studies on diets other than VLCDs (e.g. low carbohydrate diets and low fat diets) and/or effects other than sense of hunger (e.g. body weight changes, body composition and snoring). The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
No references were provided which addressed the effects of VLCDs on sense of hunger.
The Panel concludes that a cause and effect relationship has not been established between the consumption of a VLCD and reduction in the sense of hunger during a sustained energy deficit.
3.3. Redukcja tkanki tłuszczowej z utrzymaniem beztłuszczowej masy ciała (ID 1412)
The references provided for the scientific substantiation of the claim included narrative reviews, and human intervention studies on the effects of diets other than VLCDs (e.g. low carbohydrate diets, and low fat diets) on body composition. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
Ryttig and Rossner (1995) assessed body composition changes in 60 obese subjects on a diet providing 330 kcal/day for 12 weeks using tetra polar bioelectrical impedance analysis. The Panel
notes that this diet does not comply with the minimum requirement of 450 kcal/day for VLCDs, and considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
Zahouani et al. (2003) reported on a study in 1,389 obese subjects who lost on average 10.3 5.5 kg fat
mass and 2.2 2.05 kg fat free mass after 90 days on a VLCD. Body composition was assessed by leg-to-leg bioelectrical impedance analysis. Burgess (1991) found that fat mass contributed 75 % to total weight loss after 12 weeks of VLCD treatment assessed by hydro-densitometry as well as by bio-impedance analysis in 17 obese subjects (9 women). Coxon et al. (1989) randomised obese females to consume either a VLCD providing 405 kcal/day (n=12) or a VLCD providing 800 kcal/day (n=14) for eight weeks, each aimed at obtaining different rates of weight loss. Body composition was assessed by bioelectrical impedance analysis and by infrared interactance. A ratio of just over 0.4 between loss of fat free mass and total weight loss regardless of the rate of weight loss was observed. Hoie et al. (1993) assessed the quality of weight loss by near-infra-red interactance in 127 obese subjects on a VLCD for eight weeks. Mean weight reduction was 12.7 kg (12.6 % of initial weight) and mean body fat loss was 9.5 kg, which constitutes about 75 % of the weight loss. Mean reduction in lean body mass was 3.2 kg. No correlation was found between initial body mass index (BMI) and loss of lean body mass, or between initial body composition and weight loss. Morgan et al. (1992) assessed changes in body composition using total body nitrogen measured by in vivo neutron activation analysis in 11 females on a VLCD for 11 weeks. The mean loss of total body nitrogen was 125±57 g, equivalent to 781±356 g protein. The fat-free mass component of the weight loss was calculated by two different methods as 23.5 % (±3 % SEM) and 22.8 % (±2.7 % SEM), respectively.
The Panel notes that none of the studies provided assessed the effects of VLCDs on body composition compared to other dietary strategies for weight loss, that most of the studies provided used bioelectrical impedance analysis or infrared interactance for body composition analysis, both of which are not considered as reliable methods to assess changes in body composition in obese subjects during rapid weight loss, and that in most of the studies provided body fat accounted for about 70-78 %, and fat-free mass for about 22-30 %, of the total weight lost, which is, respectively, the approximate composition of the excess body weight in obese subjects and the approximate composition of the weight loss which could be expected by the use of other weight loss strategies.
In weighing the evidence, the Panel took into account that the evidence provided did not consistently show a greater reduction in body fat mass relative to lean body mass in obese subjects on VLCDs compared to other dietary interventions aimed at weight loss.
The Panel concludes that a cause and effect relationship has not been established between the consumption of a VLCD and reduction in body fat mass while maintaining lean body mass.
3.4. Zmniejszenie stężenia glukozy we krwi po posiłku (ID 1414)
A cause and effect relationship cannot be established between the consumption of a VLCD and reduction of post-prandial glycaemic responses (ID 1414).
3.5. Utrzymanie prawidłowego profilu lipidów we krwi (ID 1421)
A cause and effect relationship cannot be established between the consumption of a VLCD and maintenance of normal blood lipid profile (ID 1421)
4. Uwagi do zaproponowanego brzmienia oświadczenia
4.1. Redukcja masy ciała (ID 1410)
The Panel considers that the following wording reflects the scientific evidence: “Replacing the usual diet with a very low calorie diet helps to lose weight”.
5. Warunki i możliwe ograniczenia stosowania oświadczenia
5.1. Redukcja masy ciała (ID 1410)
The Panel considers that in order to bear the claim, a diet should comply with the specifications and conditions of use laid down in CODEX STAN 203-1995. The target population is obese adults who wish to reduce their body weight.
Wnioski
On the basis of the data presented, the Panel concludes that:
Whereas the diet, very low calorie diet (VLCD), which is the subject of the claims is sufficiently characterised in relation to the following claimed effects: reduction in body weight (ID 1410), reduction in the sense of hunger (ID 1411), and reduction in body fat mass while maintaining lean body mass (ID 1412), VLCD is not sufficiently characterised in relation to: reduction of post-prandial glycaemic responses (ID 1414) and maintenance of normal blood lipid profile (ID 1421), mainly owing to the lack of standardisation of the type of available carbohydrates and of most of the fatty acids that formula foods for use in VLCDs should contain.
A cause and effect relationship cannot be established between the consumption of a VLCD and reduction of post-prandial glycaemic responses (ID 1414) and maintenance of normal blood lipid profile (ID 1421).
Reduction in body weight (ID 1410)
The claimed effect is “safe and effective weight loss, long term weight maintenance”. The target population is assumed to be obese adults who wish to reduce their body weight. Reduction in body weight is a beneficial physiological effect.
A cause and effect relationship has been established between the consumption of a VLCD and reduction in body weight.
The following wording reflects the scientific evidence: “Replacing the usual diet with a very low calorie diet helps to lose weight”.
In order to bear the claim, a diet should comply with the specifications and conditions of use laid down in CODEX STAN 203-1995. The target population is obese adults who wish to reduce their body weight.
Reduction in the sense of hunger (ID 1411)
The claimed effect is “reduced hunger”. The target population is assumed to be obese adults in the general population. In the context of the proposed wordings, it is assumed that the claimed effect refers to a reduction in sense of hunger mediated by the induction of ketogenesis during a sustained energy deficit. Reduction in the sense of hunger during a sustained energy deficit is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of a VLCD and reduction in the sense of hunger during a sustained energy deficit.
Reduction in body fat mass while maintaining lean body mass (ID 1412)
The claimed effect is “burning fat for energy, preserving lean tissue”. The target population is assumed to be obese adults in the general population. In the context of the proposed wordings, it is assumed that the claimed effect refers to the loss of fat mass while maintaining lean body mass during weight loss. Reduction in body fat mass while maintaining lean body mass is a beneficial physiological effect.
A cause and effect relationship has not been established between the consumption of a VLCD and reduction in body fat mass while maintaining lean body mass.