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Is there a place for low-energy formula diets in
weight management?
Adrian Brown, Gary Frost, Shahrad Taheri
Citation: Brown A, Frost G,
Taheri S (2015) Is there a place
for low-energy formula diets
in weight management? British
Journal of Obesity 1: 106–13
Article points
1.Low-energy (LEDs) and verylow-energy (VLEDs) formula
diets are gaining popularity
in clinical practice, with new
EU recommendations on
appropriate formulations and
NICE guidelines on their use.
2.In conjunction with appropriate
support and behaviour change
techniques, LEDs and VLEDs
can produce significant
short- and long-term weight
loss, and even reductions in
obesity-related comorbidities.
3.Side effects are ptoentially
severe, however, and clinical
supervision is required
throughout any programme.
Key words
- Low-energy formula diets
- Very-low-energy formula diets
Authors
Adrian Brown is a Specialist
Weight Management Dietitian,
Imperial College London; Gary
Frost is Professor of Nutrition
and Dietetics, Imperial College
London; Shahrad Taheri is Visiting
Professor of Medicine, Imperial
College London and Weill Cornell
Medical College in New York,
NY, USA, and Doha, Qatar.
106
While reduction in energy intake is key to weight loss, it is challenging in practice to
achieve a sufficient calorie deficit to achieve clinically significant weight loss. With
indicators that a greater weight loss within the first year is a good predictor of long-term
weight loss maintenance, the use of dietary methods to give a substantial early energy
deficit could be beneficial. Low-energy (800–1200 kcal/day) formula diets (LEDs) and
very-low-energy (<800 kcal/day) formula diets (VLEDs) have recently gained popularity
in clinical practice as a tool to enable patients to achieve this substantial calorie deficit
and, therefore, lose a significant amount of weight, with consequent improvements in
obesity-related comorbidities. This review examines the current evidence for the use
of LEDs and VLEDs for weight loss and improvements in obesity-related comorbidities,
while helping to inform clinicians on their potential use in clinical practice.
O
besity has reached epidemic proportions
worldwide, necessitating effective weight
loss interventions and strategies for weight
loss maintenance. Evidence shows that traditional
popular dietary approaches produce, at best,
between 5.3 and 7.27 kg of weight loss at 12 months
(Avenell et al, 2004; Johnston et al, 2014), and an
even lower degree of weight loss in primary care
(Jolly et al, 2011). While a 5–10% weight loss has
significant health benefits, it may be insufficient to
give sustained and perceptible benefits for people
with greater degrees of obesity (BMI ≥35 kg/m2)
complicated by serious medical complications
(SIGN, 2010). Currently, bariatric surgery appears
to be the most effective therapy in terms of both
sustained weight loss and treatment of comorbidities
in severe obesity (Buchwald et al, 2004; Sjöström,
2013). When compared with non-surgical
interventions, the weight loss achieved by bariatric
surgery is associated with superior weight reduction,
improved sleep quality, improved quality of life,
and better glycaemic control (Dixon et al, 2008;
Schauer et al, 2014). However, notwithstanding the
methodological issues inherent in studies of bariatric
surgery, not every patient wishes to undergo these
procedures and, despite guidelines from NICE
and other organisations, lack of funding limits
accessibility to bariatric surgery, with only 1–2% of
eligible patients receiving it (Dixon et al, 2011).
While the causes and pathophysiology of obesity
are complex and still poorly understood (Cope
and Allison, 2006), obesity primarily results
from excessive calorie intake compared to calorie
expenditure. With a heavier, ageing population
with increased rates of osteoarthritis and limited
mobility compared with the past (Leeds, 2014),
effective dietary manipulation is crucial for obesity
management in the vast majority of patients in
clinical weight management services. Conventional
dietary approaches lead to weight loss of only
0.5–1.0 kg per week, making them a daunting task
for individuals who need to lose a lot of weight.
Low-energy formula diets (LEDs), however, are
able to create dietary energy deficits similar to those
British Journal of Obesity Volume 1 No 3 2015
Is there a place for low-energy formula diets in weight management?
achieved following bariatric surgery, and they have
the potential to fill this therapeutic void between
surgery and traditional therapy.
Very-low-energy and low-energy
formula diets
Very-low-energy formula diets (VLEDs) are defined
as hypo-calorific diets that provide 450–800 kcal
(1884–3350 kJ) per day and replace the whole
diet with prepared formula, usually in the form of
liquid shakes, soups and bars (Atkinson et al, 1993;
Codex Alimentarius, 1995; NICE, 2014). These
are enriched by high-biological-value protein and
provide 100% of the Dietary Reference Value for
vitamins and minerals within a defined number
of servings. Previously, a minimum daily energy
intake of 450 kcal was suggested; this has recently
been revised by the European Commission,
which now recommends that a minimum of
600 kcal/day should be provided (European Food
Safety Authority, 2015). In comparison, LEDs
provide 800–1200 kcal (3350–5021 kJ) per day,
with each meal replacement needing to provide
200–400 kcal per meal (Codex Alimentarius, 1991).
Within the medical literature, the terms “verylow-calorie” and “very-low-energy” have often
been used interchangeably. As calories are units of
energy, however, the latter is the preferred definition
(Scientific Cooperation Committee, 2002) and
will be used in this review. VLEDs have been
reported in the medical literature for over 85 years.
Evans and Strang (1929) published data on a
ketogenic diet providing 6–8 kcal/kg, with 35%
and 38% of the calories coming from protein and
fat, respectively. They reported on more than 100
patients, who benefited from excellent weight loss
with minimal side-effects. In the 1970s, VLEDs
were popularised in the publication The Last Chance
Diet (Linn, 1976). Original formulations not only
included low-biological-value protein (hydrolysed
collagen) but were also deficient in electrolytes and
minerals, and they resulted in at least 60 fatalities
owing to intractable ventricular arrhythmias (Sours
et al, 1981; Wadden et al, 1983a). During this
same period, formulations were developed that
eliminated the previously seen arrhythmias (Felig,
1984). Since then, there has been a substantial
amount of research within this area regarding
optimal composition to minimise protein turnover,
British Journal of Obesity Volume 1 No 3 2015
maintain nitrogen balance and ensure that essential
micronutrient requirements are met.
Both LEDs and VLEDs are designed to produce
rapid weight loss while maintaining fat-free body
mass. VLEDs are designed to induce ketosis,
during which controlled fasting and restriction of
dietary carbohydrate causes fatty acid oxidation in
the liver to form transformable energy, while also
mediating suppression of ghrelin (Atkinson et al,
1993, Sumithran et al, 2013). However, owing to
higher energy intakes, these effects might not be as
prevalent in LEDs. LEDs are regulated in the EU
by Directive 96/8/EC and by the European Food
Safety Authority (EFSA). Compositional, labelling
and advertising requirements for the use of LED
total meal replacements are outlined within the
Directive. Remarkably, VLEDs were not included
within the original EU Directive, although they
were subject to regulation and recommendations
within the Codex Alimentarius Standard in the UK.
Recently, the European Commission requested
that the EFSA provide a scientific opinion on the
essential composition of total diet replacements
for weight control and update the Directive to
include VLEDs. The EFSA proposed several key
recommendations (EFSA, 2015):
lFormulations should include the following:
– Between 75 g and 105 g of high-quality protein
per day, to maintain protein turnover.
–A minimum of 30 g of digestible carbohydrate
per day.
–At least 11 g of linoleic acid and 1.4 g of
alpha-linolenic acid per day.
– A minimum of around 20 g of total fat per day,
to ensure sufficient levels of essential fatty acids.
–A minimum energy content of 600 kcal
(2510 kJ) per day.
–
Daily micronutrient intake derived from
Population Reference Intakes or Adequate
Intakes, based on previous opinion.
l
Individualised specialist medical advice is
required for individuals with obesity-related
comorbidities.
lFluid intake during energy restriction should be
2.5 L/day for men and 2.0 L/day for women.
Page points
1.A low-energy diet (LED)
provides 800–1200 kcal per
day, with each formula meal
providing 200–400 kcal. A
very-low-energy diet (VLED)
provides 450–800 kcal per day.
2.Both types of diet are designed
to produce rapid weight loss
while maintaining fat-free body
mass. However, VLEDs go
further by inducing ketosis.
3.New EU recommendations
state that VLED formulations
should provide at least
600 kcal per day, along with
sufficient levels of protein,
digestible carbohydrate, fat,
micronutrients, linoleic and
alpha-linoleic acid per day.
Owing to a lack of scientific evidence, no
recommendations were made for minimum fibre
intake; however, additional fibre is often provided,
107
Is there a place for low-energy formula diets in weight management?
Page points
1.Both LEDs and VLEDs have
been shown to produce
significant weight loss over
periods of 4–24 weeks,
with data suggesting that
greater weight loss occurs
with longer diet durations.
2.Contrary to the expectation
that greater energy restriction
should lead to greater weight
loss, there is little evidence that
VLEDs produce greater weight
loss than LEDs in the long term.
3.Recent evidence suggests
that VLEDs can be effective
in promoting long-term
weight loss and maintenance,
but only if supported with
behaviour change techniques,
especially around the time of
reintroducing conventional
food after the diet.
with around 7–10 g advised (Saris, 2001). Notably,
legislation concerning the definition, composition,
labelling, directions of use and availability of LEDs
varies considerable across Europe and worldwide
(Scientific Cooperation Committee, 2002).
Effects on weight loss
Short-term weight loss
Studies have shown that both VLEDs and LEDs
are effective at promoting significant weight loss in
the short term (up to 24 weeks), with concomitant
improvements in obesity-related comorbidities
(Atkinson, 1993; Johansson et al, 2009; Christensen
et al, 2011; Mulholland et al, 2012). In the medical
literature, the length of time on these diets varied
between 4 and 24 weeks (Wadden et al, 1983b),
with initial weight losses of 1.4–2.5 kg per week
and suggestions that the longer the period of
calorie restriction the greater the weight loss (Saris,
2001); however, prolonged calorie restriction can
potentially affect compliance in the long term.
Despite the theoretical idea that VLEDs should
produce greater weight loss because of greater energy
restriction, this has not been shown to be the case
over the long term (Saris, 2001; Norris et al, 2005;
Lin et al, 2009; Christensen et al, 2011). In a metaanalysis of six randomised controlled trials, initial
short-term weight loss was significantly greater
following VLEDs compared to LEDs (16.1% vs.
9.7% of initial weight; Tsai and Wadden, 2006).
This difference, however, was not sustained over
time. A concern is that only one of the studies
used an intention-to-treat (ITT) analysis, whereas
the others biased the results by only analysing
completers.
The lack of short-term difference was further
demonstrated by a randomised controlled trial
(Christensen et al, 2011). Here, at both 8 weeks
and 16 weeks, there was no significant difference in
weight loss between participants who used a VLED
(420–554 kcal/day) and those who used an LED
(810 kcal/day).
In clinical practice, if rapid weight loss is required
(e.g. for a total knee replacement), using a formula
diet for a period of 8–12 weeks has clear benefits
(Leeds, 2014; NICE, 2014).
Long-term weight loss and maintenance
In the long term, weight loss with VLEDs and
108
LEDs has been shown to be similar, owing to
greater weight regain following cessation of a
VLED. In Tsai and Wadden’s (2006) systematic
review, over a mean follow-up of 1.9 years, the mean
long-term weight loss was 6.3±3.2% and 5.0±4.0%
in the VLED and LED groups, respectively, with
the VLED group having regained 62% of the
weight loss compared to 41% in the LED group.
Often the challenge with weight maintenance
begins during the reintroduction of conventional
food after the diet, especially if the individuals have
not addressed the reasons for their initial weight
gain. The use of behavioural techniques alongside
formula diets are essential to aid weight loss
maintenance and help the participants address their
relationship with food, while also losing weight.
Three recent studies, including two systematic
reviews, have shown that long-term weight loss
maintenance is possible following a VLED with
the addition of weight loss maintenance strategies
(Mulholland et al, 2012; Christensen et al, 2014;
Johansson et al, 2014). Exercise, behaviour change
therapy, medication and a longer reintroduction
phase post-VLED all helped people to maintain
greater weight loss (Mulholland et al, 2012).
These observations are further supported by
studies showing that anti-obesity drugs, extended
use of low-energy meal replacements (one per
day) and high-protein diets are associated with
improved weight loss maintenance (Christensen
et al, 2014; Johansson et al, 2014). Interestingly, in
these studies, exercise did not result in significant
improvements (Johansson et al, 2014). It must be
noted that two of the three drug studies reviewed
by Johansson and colleagues involved sibutramine, a
drug that was withdrawn in 2010.
The commonly held belief that slow weight
loss is better preserved than more rapid loss is
in contrast to recent evidence, which shows a
positive correlation between larger initial weight
loss and long-term weight maintenance (Astrup
and Rössner, 2000; Wadden et al, 2011; Rolland
et al, 2014). The Look AHEAD study, which
compared an intensive lifestyle intervention with
conventional education and diabetes support in
over 5000 people with type 2 diabetes, showed that
the greatest determinant of weight maintenance
at 4 years was the loss of ≥10% of baseline weight
within the first year (Wadden et al, 2011). More
British Journal of Obesity Volume 1 No 3 2015
Is there a place for low-energy formula diets in weight management?
support for this position comes from a randomised
trial of 204 participants comparing rates of weight
regain following a weight loss of ≥12.5% using either
a rapid (12-week) or gradual (36-week) weight loss
programme (Purcell et al, 2014). The rate of weight
loss did not affect the degree of weight regain over a
144-week period, with both groups regaining 76.3%
of the weight loss in the ITT analysis. Therefore,
interventions that enable a greater initial weight loss
could be more effective in terms of long-term weight
maintenance.
The place of low-energy formula diets in
clinical practice
At present, the use of VLEDs and LEDs within
clinical practice remains a rarity amongst healthcare
professionals. The belief that the high rate of weight
loss and the regain of weight following cessation
are detrimental remains a concern (NICE, 2014);
however, this position has started to be challenged
(Christensen et al, 2014; Johansson et al, 2014;
Rolland et al, 2014). Furthermore, the vast majority
of research for formula diets has been in people
with a BMI between 30 and 40 kg/m2, while the
evidence for their use within the extreme obese
population (BMI >40 kg/m2) remains sparse (Leeds,
2014; NICE, 2014). Much of the evidence in the
latter population comes from people using VLEDs
for 2–6 weeks prior to bariatric surgery to help
rapidly reduce liver fat and volume – the so-called
“liver shrinkage diet” (Fris, 2004; Colles et al, 2006;
Lewis et al, 2006). Despite this, within clinical
practice in the UK, 49 preoperative diets have been
observed in current use (Baldry et al, 2014), which
raises the question of whether bariatric services
should continue using preoperative diets that have
no evidence base behind them.
The latest update of the NICE obesity guidelines
(CG189; NICE, 2014) reviewed the evidence for
using VLCDs in people with a BMI >40 kg/m2,
which was only briefly addressed in the original
2006 guidelines. NICE now recommends that
VLEDs should not routinely be used within
clinical practice to manage obesity (defined as BMI
>30 kg/m2) and only in people with a clinically
assessed need to rapidly lose weight, such as those
who are seeking fertility services. Additionally,
VLEDs should be used in conjunction with a longterm, multicomponent weight management service,
British Journal of Obesity Volume 1 No 3 2015
including psychological assessment and discussion
regarding risks, benefits and possible weight regain
after reintroduction of food. VLEDs should only be
followed for a maximum of 12 weeks, continuously
or intermittently. Interestingly, LEDs (>800 kcal/day)
were only briefly mentioned in the 2014 update and
were not included in the above review.
Other position statements from the National
Obesity Forum (NOF, 2010) and the British
Dietetic Association’s obesity special interest group,
Dietitians in Obesity Management UK (DOM
UK, 2007) further add to these recommendations,
although neither statement currently supports every
recommendation made by NICE. Within both
statements, VLEDs can be considered for people
with a BMI ≥30 kg/m2, and medical supervision is
needed for those with obesity-related comorbidities.
In addition, NOF suggest no time limit or age limit,
as long as monitoring and medical supervision are
included, and they suggest that GP approval is not
required for all patients, provided that adequately
trained staff delivers the programme.
The issue of weight cycling was highlighted in
the NICE guidelines, as epidemiological studies
indicate that this increases the risk of morbidity and
mortality (Lissner et al, 1991), as was the potential
psychological effect of weight regain. However,
identifying the difference between intentional and
unintentional weight loss is difficult, and in a recent
systematic review it was concluded that there was
no causal association of weight cycling with early
mortality or morbidity, with evidence being sparse
regarding any negative impact (Mehta et al, 2014).
As studies are often conducted in diverse
populations and countries, the implementation of
weight loss interventions, including those utilising
LEDs, within clinical practice can be challenging.
Two UK studies observing the use of VLEDs and
LEDs in commercial and clinical environments
have recently been published. In a feasibility study
conducted within primary care, investigators from
the Counterweight Programme used an LED in
patients with a BMI of ≥40 kg/m2 (Lean et al, 2013).
With structured food reintroduction and weight
maintenance, with optional orlistat in the first
year of treatment, the participants (68 completers,
out of 91 enrolled) recorded mean weight losses of
12.4±11.4 kg, with 30% achieving ≥15 kg of weight
loss at 12 months. Importantly, it was also observed
Page points
1.VLEDs are not recommended
for use in routine practice in
the current NICE guidelines;
rather, they are recommended
only for people with a
clinical need for rapid weight
loss and in conjunction
with a long-term weight
management programme.
2.The National Obesity Forum
and Dietitians in Obesity
Management UK both have
their own recommendations
to supplement the
NICE guidelines.
3.While there is concern over
epidemiological studies
showing that weight cycling
increases morbidity and
mortality, such studies
cannot distinguish between
unintentional and intentional
weight loss, and a recent
meta-analysis concluded that
there was no causal link.
109
Is there a place for low-energy formula diets in weight management?
Page points
1.Significant long-term
improvements in weight-related
comorbidities have been
observed following VLEDs,
and there is growing evidence
that VLEDs can improve or
even reverse type 2 diabetes.
2.In addition to improving insulin
resistance and lipid profiles,
VLEDs have been shown to
improve cardiac function,
psoriasis, osteoarthritis and
obstructive sleep apnoea;
however, the evidence for
these outcomes is conflicting.
3.The evidence base for the
effects of LEDs on type 2
diabetes is less solid, with
study limitations and biases
reducing the generalisability
of the findings.
that the programme might be cost-effective within
the primary care setting. In further support of this,
a retrospective analysis between 2007 and 2010
of 5965 participants commencing a commercial
VLED programme, with additional behaviour
change therapy, demonstrated a mean weight loss of
18±11.4 kg and 12.9±10 kg after 1 year and 3 years,
respectively (Rolland et al, 2014). While both of
these studies had limitations, including the lack of
randomisation, selection bias, and significant dropout rates, they show that, in motivated patients, an
LED approach combined with behaviour change
therapy can successfully achieve clinically significant,
maintainable weight loss.
Another clear advantage of formula diets is their
ability to remove food from the daily decisionmaking process (Leeds, 2014) while providing a
person with a known amount of calories (Purcell et
al, 2014). This can allow participtants to focus on
introspectively looking at their relationship with
food, identifying the difference between emotional
and physical hunger and gaining skills to aid longterm weight maintenance.
Low-energy formula diets in people with
type 2 diabetes, cardiovascular disease and
other obesity-related comorbidities
Significant long-term improvements in weightrelated comorbidities have been seen following
VLEDs (Tsai and Wadden, 2006). Current
evidence with a minimum follow-up of 12 months
suggests that weight loss and improvements in
waist circumference, blood pressure and lipid
profiles occur following a VLED (Mulholland
et al, 2012). With evidence that the calorie
restriction immediately following bariatric surgery
is pivotal to the observed improvements in glucose
homeostasis (Lips et al, 2014; Plourde et al, 2014),
and that ectopic fat (particularly within the liver
and pancreas) is a key part of the aetiology of type 2
diabetes (Taylor, 2013), there is now mounting
evidence for the effective use of LEDs in people
with type 2 diabetes. This was supported by a small
pilot study of 11 people with type 2 diabetes who
underwent a VLED for 8 weeks (Lim et al, 2011).
These participants showed normalised hepatic
insulin sensitivity and beta-cell function, which was
directly associated with reduced triacylglycerol levels
in the liver and pancreas, respectively. Moreover, in
110
another study of the same diet in 29 people with
type 2 diabetes, of the 14 participants with longduration diabetes (>8 years), fasting plasma glucose
levels normalised in 50% (Steven and Taylor, 2015).
These findings suggest that acute energy restriction
could reverse the abnormalities typical to type 2
diabetes.
Further studies have looked at LEDs in
people with type 2 diabetes receiving either
oral hypoglycaemic agents or insulin, showing
significant improvements in weight, glycaemic
control, cardiovascular disease and quality of life
(Paisey et al, 2002; Dhindsa et al, 2003; Snel et al,
2012a; 2012b; 2012c). However, methodological
limitations, including lack of control groups,
selection bias and only reporting completers, affect
the generalisability of these findings and hamper
translation to best clinical practice.
Oral hypoglycaemic medications and insulin
require significant dose reductions following
initiation of an LED or VLED, in order to
reduce the risk of hypoglycaemia. Haslam et al
(2010) recommend gradual titration of dietary
energy intakes down to the target intake, in
order to avoid rapid changes in insulin dose, and
a possible pre-emptive reduction of insulin by
25% at commencement of an LED (Haslam et
al, 2010). It should also be noted that people with
advanced stages of type 2 diabetes might be at risk
of hyperglycaemia if all diabetes medications are
ceased.
Weight loss has been shown to improve not
only insulin resistance but also cardiac function,
with the degree of weight loss being key to these
improvements (Rider et al, 2009; Jonker et al,
2014). VLEDs reduce both cardiovascular risk and
its associated surrogate markers (Mulholland et
al, 2012), with a 16-week VLED being associated
with decreased myocardial triglyceride content
and improved diastolic function (Hammer et al,
2008). Other benefits of formula diets include
improvements in psoriasis (Jensen et al, 2014),
osteoarthritis (Christensen et al, 2011; 2014) and
obstructive sleep apnoea (Johansson et al, 2011).
However, it must be appreciated that non-favourable
evidence is also present within the literature (Tsai
and Wadden, 2006; Mulholland et al, 2012).
Clearly, further high-quality research is still
required to confirm findings and translate them
British Journal of Obesity Volume 1 No 3 2015
Is there a place for low-energy formula diets in weight management?
into everyday clinical practice, particularly in those
areas in which evidence is currently lacking, such as
liver and kidney disease and the use of these diets
within intermittent fasting regimens.
Table 1. Advantages and disadvantages of low-energy and
very-low-energy formula diets within clinical practice.
Advantages
Disadvantages
Attrition
Accurate calorie management
Constipation
The perceived rate of attrition is a significant
deterrent for people considering LEDs. Attrition
rates vary depending on the initial intervention
and follow-up, with figures ranging between
0% and 52%, and there is very little difference
between VLEDs and LEDs (Tsai and Wadden,
2006; Christensen et al, 2011). Drop-outs occur
throughout the patient journey, albeit more
frequently during the follow-up period (Mulholland
et al, 2012), when people potentially regain some
of the weight lost. Within the actual diet period,
poor compliance, work schedules and dislike of the
products commonly feature as reasons for dropping
out, while younger participants and those with a
higher BMI more often drop out during followup (Mulholland et al, 2012). Interestingly, when
compared with conventional dietary approaches,
meal replacements can aid both compliance and
perceived convenience (Noakes et al, 2004).
Nutritionally complete
Flatulence
Significant weight loss
Feeling the cold
Improvement in glycaemic control
Dizziness and hypotension
Reduced cardiovascular risk markers
Nausea
Improvement in sleep apnoea
Diarrhoea
Improvement in general quality of life
Gallstones
Benefits for osteoarthritis
Headache
Improvement in psoriasis
Acute gout
Benefits for mood
Halitosis
Removal of food from the daily
decision-making process
Sleep disturbance
Side-effects
Table 1 shows the advantages and disadvantages
of LEDs. During the initial stages of rapid weight
loss with these diets, individuals may experience
side-effects such as hair loss, fatigue, dizziness,
constipation, acute gout, cold intolerance,
headaches, muscle cramps and gallstones (Wadden
et al, 1983b; Saris, 2001). In a recent randomized
controlled trial, at 8 weeks, compared with LED
users, VLED users had a significantly higher
incidence of bad breath (35% vs. 22%), intolerance
to cold (41% vs. 18%) and flatulence (45% vs. 28%;
P<0.05 for all comparisons), with trends towards
greater risk of hair loss and dry skin (Christensen
et al, 2011). Mirroring previous findings, this study
suggested that LEDs have fewer adverse effects
than VLEDs, and this should be considered when
choosing between the two diets (Rössner and Flaten,
1997).
Patients should also be made aware that acute
gallstone events and gout have been reported
following significant weight loss (Christensen et al,
2011; Johansson et al, 2011). However, incidences
British Journal of Obesity Volume 1 No 3 2015
of gallstone disease have mostly been reported in
the US, where formula diets contain lower levels of
essential fatty acids than in the EU (Saris, 2001).
Side-effects with formula diets are generally
mild and easily managed, although, if VLEDs are
used unsupervised in high-risk individuals, they
may result in serious complications (Wadden et al,
1983b). VLEDs cannot be used with every patient
and there are currently several contraindications to
their use, including pregnancy, acute kidney disease
and gout (Box 1).
The loss of excess lean body mass following
LEDs poses several risks (Heymsfield et al,
2014), and lean tissue losses of 14–30% have been
reported, depending on the patient population and
the inclusion of physical activity in the regimen
(Christensen et al, 2011; Snel et al, 2012a).
Sufficient amounts of protein and associated
carbohydrate are essential to minimise protein
turnover and maintain nitrogen balance. Hopefully,
with the new EU regulations, loss of lean body mass
will continue to be minimised.
Research has suggested that poor diet quality
and micronutrient deficiencies are more common
in obese individuals compared to normal-weight
people (Kimmons et al, 2006; Damms-Machado
et al, 2012). With evidence that traditional popular
111
Is there a place for low-energy formula diets in weight management?
“The use of lowenergy diets has been
shown to be effective
in producing clinically
significant weight
loss and, with the
addition of weightloss maintenance
strategies, can produce
a long-term body
weight loss of around
10%, combined
with improvements
in obesity-related
comorbidities.”
Box 1. Contraindications for the use of
very-low-energy diets.
• Infants and children.
• Pregnancy and lactating women.
• Unstable cardiac or cerebrovascular disease.
• Acute and chronic renal failure.
• Severe or end-stage liver failure.
• Acute psychiatric disorder.
•Gout.
weight loss diets have a high likelihood of being
micronutrient-deficient (Calton, 2010), theoretically,
formula diets that provide 100% of the Daily
Reference Intake for healthy adults could help
to improve these deficiencies during weight loss.
Evidence is variable, suggesting both improvements
and further deteriorations in nutritional status
in obese individuals who follow a formula diet
(Damms-Machado et al, 2012; Christensen et al,
2013). Undoubtedly, further evidence is required.
Conclusion
The use of LEDs has been shown to be effective in
producing clinically significant weight loss and, with
the addition of weight-loss maintenance strategies,
can produce a long-term body weight loss of around
10%, combined with improvements in obesityrelated comorbidities. Evidence is now growing
for the use of VLEDs within both diabetes and
osteoarthritis. Furthermore, the erroneous beliefs that
LEDs are unsafe and that the rapid weight loss is not
maintained are increasingly being challenged.
At present, it is difficult to recommend best
practice regarding LEDs (Mulholland et al, 2012;
Johansson et al, 2014). Although higher-quality data
have been published more recently, previous papers
often only reported data on completers and had
significant methodological heterogeneity. This has
been reflected by the differing statements from the
professional bodies and the fact that NICE (2014)
does not yet recommend VLEDs in routine care.
From the current scientific evidence, it appears
that LEDs may have a place within weight
management and clinical practice; however, if
clinicians are to consider them, it is important that
the right infrastructure be in place to support the
patient, in order to ensure both safety and weight
maintenance. With research in this area gaining
112
momentum, the use of LEDs in routine care may
indeed change in the future.
n
Conflicts of interest
The authors have received funding for investigatorinitiated research through an educational grant
from Cambridge Weight Plan Ltd.
Acknowledgement
Shahrad Taheri receives funding from the
Biomedical Research Program (BMRP) at Weill
Cornell Medical College in Qatar, supported by the
Qatar Foundation, and from the Qatar National
Research Fund National Priorities Research
Programme (NPRP), grant no. NPRP 8-912-3-192.
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“From the current
scientific evidence,
it appears that lowenergy diets may
have a place within
weight management
and clinical practice;
however, if clinicians
are to consider them,
it is important that the
right infrastructure
be in place to support
the patient, in order to
ensure both safety and
weight maintenance.”
113