Transcript The Evidence - DCU Moodle 2013

Weight Reduction Diets
The Evidence
18th October 2012
Sarah Browne
Dietitian, MINDI
Principles to achieve weight loss
• Reduce energy intake
– Usually by 500 kilocalories per day
• Increase energy expenditure
– Gradual increase to 1 hour moderate intensity exercise per day
• The desirable rate of weight loss is 0.5kg-1 kg per week
= sustainable & maintainable
• Dietary therapy involves helping patients modify dietary intake while
maintaining a nutritionally balanced diet.
• Faster rates of with larger the daily deficit in energy balance but
may include excessive loss of lean tissue
TARGETS & GOALS
• Target of a weight loss programme should be to decrease
body weight by 5-10%
• Once achieved a new target can be set
• Even a weight loss of 5% is clinically significant, improving
cardiac risk factors, risks of co-morbidities and mortality
• To estimate actual energy requirements of the patient the
resting metabolic rest (RMR, kcal/day) is multiplied by an
activity level (PAL)
• The prescribed energy intake of weight reducing diet is the
individuals actual energy requirement minus the prescribed
daily energy deficit
Geissler, C. and Powers, H. (2011) Human Nutrition, 12th edn. pp 413-423.
Know any popular
slimming groups/ programmes?
Commercial Weight Loss Programmes
(CWLP)
Weight Watchers
Unislim
• Based on a ‘ProPoints’plan
‘designed to fit around real life
so that weight loss becomes
part of your daily routine’
• Provide you with a personalised
weekly meal plan ‘tailored to
your lifestyle, activity level, food
preferences, health requirement,
favourite supermarket and weight
loss goals’.
– Each food has a ProPoints value
– Member is given a ProPoints
budget for the week which
consists of a daily allowance
(based on your gender, age,
weight and height)
– Set 5% & 10% goals
– All fresh fruit and most veg are
free from Propoints
– Weekly meetings & weigh in
– Aim: 1-2lbs weight loss per week
– plan based on healthy GI-friendly
eating and free foods
– Weekly meetings & weigh in
– Aim: 1-2lbs weight loss per week
CWLP – Do they Work?
• Support element beneficial – weekly contact with
information/advice & others in same situation
• Weekly weigh in – motivating effect
• NHS in UK have referral scheme to weight watchers where
patients receive vouchers to attend for12 weeks
– Average weight loss 3% of body weight
– 33% lost more than 5% of body weight
– 54% completed the 12 week course
• That group lost more – 5.6% of original weight
(Audited by Ahern et al, 2011)
Meal Replacement Diets (MR)
• Portion controlled products designed to replace
one to two meals per day in conjunction with a
low calorie meal & snacks
• Examples include Slim-fast, Special K diet,
Celebrity Slim
• Advantages are easy portion control, there is a
‘plan’ to follow, don’t have to count calories
• Work by reducing overall calorie intake
• Long-term benefits for weight loss &
maintenance inconclusive in literature
Very low calorie diets (VLCD)
– Diets that provide 400-800kcal a day
– Should be used under medical supervision of trained health
professional – e.g. doctor with dietitian
– Mostly indicated in upper obesity where
BMI >
35/40km-2
– With very low calorie content it’s impossible to create a
balanced VLCD diet using ordinary foods alone. VLCD diets
are composed of high protein low carbohydrate products
(with RDA of all minerals, vitamins, trace elements and
essential fatty acids). Examples:
– Lipotrim (pharmacy based) – shakes, bars
– Orsmond clinic – shakes, high protein pasta, bars, cereal and
muffins, green vegetables also allowed
Very low calorie diets (VLCD)
– Only source of nutrition for duration of
programme (8-16 weeks)
– Results in fast rate weight loss – 1.5kg+ per
week
– ‘Ketogenic diet’ where carbohydrate is limited
– Body uses mainly fat stores for energy
purposes, ketone bodies are released as a
'waste product’ of fat metabolism – help to
supress appetite
VLCD – Do they work?
• They certainly result in weight loss
• Weight gain risk is high with re-introduction
of regular diet
• Supervised & supported re-introduction phase
important to prevent shifts in fluid,
electrolytes and to prevent abdominal
discomfort
Low Fat Diets
• Recommended that our energy intake from food is broken down as
follows:
– 55% from Carbohydrate
– 30% or less from Fat
– 15% - 20% from Protein
• The diet of Irish adults provides about 35% energy from fat (Irish
Adult Nutrition Survey, 2011 – www.iuna.net)
• Per gram, fat has a higher energy content than carbohydrates or
protein – 1g fat = 9 kilocalories, while 1g carbs/protein = 4
kilocalories (1g alcohol = 7 kilocalories)
• Fat calories will be stored as adipose tissue while carbohydrate,
alcohol and protein calories are used first for energy due to the
body’s limited capacity for storage of them
Low Fat Diets – do they work?
• A low-fat diet is one where fat intake represents less than 30%
of overall energy intake
• Usually target reduction in saturated and trans fats so
healthier fats – unsaturated and essential fatty acids – are still
present in the diet
• Four meta analyses of weight change occurring on low-fat
diets consistently demonstrate a highly significant weight loss
of 3-4 kg in normal-weight and overweight subjects
• Weight loss is also positively related to initial weight: a 10 %
reduction in dietary fat (e.g. if intake is 80g, reduce to 72g) is
predicted to produce a 4-5kg weight loss in an individual with
a BMI of 30 kg/m-2 (Astrup et al, 2002)
Low Carbohydrate Diets
• Limits grains, starchy veg, fruit, potato, rice, pasta, bread &
emphasises more protein & fat
• Restriction depends on programme followed
• Extra fat & protein can leave you feeling fuller for longer
• Also a ‘ketogenic diet’, where the body is mainly using fat for
energy & the by-products are ‘ketones’. Ketones can cause
side-effects like bad breath, headaches, nausea
• Important that not missing out on key vitamins carbohydrates
usually provide – e.g. B vitamins during prolonged low-carb
diets
Low Carbohydrate Diets
• There is insufficient evidence to make recommendations about the
use of low-carbohydrate diets (Nordmann et al, 2011)
• Weight loss while on low-carbohydrate diets seems to be realated
to decreased caloric intake & increased diet duration (Bravata,
2003)
• However, low-carbohydrate diets seem to have no significant
adverse effect on serum lipid, fasting serum glucose, and fasting
serum insulin levels, or blood pressure (Bravata et al, 2003)
• Conversely, low fat, high protein/carbohydrate diets appear to be
more effective for long term weight maintenance and prevention of
weight gain (Geissler & Powers, 2011)
• Long-term effects of high protein intakes on kidneys, bones not fully
known yet
Low GI Diets
• GI = Glycaemic Index
• It measures how fast a carbohydrate food
enters the blood stream as glucose
• Foods are referred to as ‘low’, ‘medium’ or
‘high’ GI
• Low GI foods are gradually digested and enter
the blood stream as glucose slowly – e.g.
porridge oats, fruit, dairy products
• Often used to manage conditions like
Low GI Diets – do they work?
• They lower post-prandial insulin levels which
is thought to reduce fat storage & improve fat
metabolism
• Overall low GI diet is as effective, if not more
effective than other dietary alternatives in
inducing weight loss (Esfahaini et al, 2011)
Person-centred care
• Treatment and care should take into account
people’s individual needs and preferences
• Assumes that individual is best placed to make
decisions about their health & pracitioner helps
facilitate change by providing evidence-based
information at the correct time
• Good communication is essential for:
– Interpersonal Skills (building rapport, trust)
– Motivational Techniques
– Behavioural Change Tools
Person-centred care
Typical consultation would address the following:
• ‘Setting the scene’ –
– Weight history
– Dieting history
– Motivation assessment
– Current lifestyle & how food / exercise fits in
• Addressing potential barriers & plans to deal with them
• Realistic weight loss target with a time frame
• Goal setting – 2-3 achievable, very specific diet & exercise goals
with time frame & review system
• Reward system based on lifestyle changes rather than weight loss
Drugs Used In The Treatment Of Obesity
• Considered for BMI>30Kg/m² and/or a BMI>27Kg/m² with comorbidities
• Drug use in treatment of obesity has been approved by NICE (2006)
and studies prove that drug use is effective in tackling obesity
• Reductil
– Withdrawn from use in Ireland in January 2010 due to increased risk of
serious cardiovascular events in patients with CVD treated with this
medicine
– Risk also considered applicable to patients without diagnosed CVD
• Xenical or Orlisat
– Indicated for obesity management in conjunction with reduced calorie diet.
– The dose is one 120mg tablet three times per day with each meal containing fat.
Xenical
• Should be teamed with a nutritionally balanced and reduced
fat diet that contains less than 30% of calories from fat
• Blocks the action of gastric and pancreatic lipases
• Therefore, one third of fat consumed is not absorbed.
• Undigested fat is excreted in the faeces
• Oily stools, abdominal pain and leakage of faecal matter are
known side effects
• Shown to produce sustained weight loss over 1 year period
compared to placebo group (Broom et al, 2002)
Bariatric Surgery
• Two types of gastric
surgery
• Gastric Bands
– Silicone band is placed around upper part of
the stomach to create a small stomach
– The band is inflated to tighten and create the
pouch
– Pouch capacity is 20-25ml
– It is reversible
Bariatric Surgery
Gastric Bypass, Roux en-Y
•Creates a small stomach pouch from which the rest of the
stomach is permanently separated.
•The small intestine is cut and re-arranged to provide an outlet
to the small stomach, while maintaining the flow of digestive
juices.
•The lower part of the stomach is bypassed, and food enters the
second part of the small bowel within about 10 minutes. Bilio
Bilio Pancreatic Diversion
•2/3 of stomach removed.
•Y shaped section of small intestine is attached to a pouch with
small alimentary channel of 50cm where it enters the colon.
•By bypassing the first two segments of the SI nutrient
absorption is significantly reduced.
•Creates significant weight loss through malabsorption.
Bariatric Surgery
•
NICE (2006): Surgery is to be considered where BMI > 40Kg/m-² (35Kg/m-²
with co morbidities) or first line option if BMI > 50Kg/m-²
The Evidence
• Conventional treatment for the morbidly obese has not been considered to be
effective over long term (Baxter, 2000 and Shah et al, 2007)
• The Swedish Obese Subjects Study has followed 4047 obese subjects over 15
years and results show surgery patients have reduced mortality rates and a
better quality of life (Sjostrom et al, 2007)
• Met-analysis has shown gastric bypass and gastric band patients lost 61.6%
and 47.5% body weight respectively (Buchwald et al, 2004)
• The majority of weight loss is achieved 1 year post surgery (Fujioka, 2005)
Risks:
• Risk of death 1:200 surgeries (bilio pancreatic diversion)
Postoperative Issues
• Restrictive procedures
– Early satiety (<1000kcal per day initially)
– Vomiting/Swallowing difficulties
– Separate consumption of food and fluid
– Selective food intolerance
– Diarrhoea- most common with consumption of
high sugar or high fat foods
– Constipation-drinking insufficient fluid
– After 6-12 months physiological adaptations may
lead to increased Kcals
Nutritional Issues
– Dumping syndrome- When easily absorbed sugar
is eaten too much insulin is produced and blood
sugar levels drop
– Protein Energy Malnutrition- uncommon but need
to assess intake and requirements
– Gallstones and hair loss (1 in 20)
– Iron deficiency- seen in 33%-50% of patients. Due
to bypassing of absorptive site/ decreased haem
intake
– B 12 deficiency- often does not respond to typical
multivitamin dose
Case Study
•
Catherine Brady presents for weight loss advice. Her weight is 95kg, height 165cm and waist
circumference of 96cm. She has a history of weight cycling and is keen to alleviate the
symptoms of shortness of breath and chest pain. She is 46 years old and works as a secretary
in a travel agents for 10 years. She travels to work every day by bus and has her lunch in one
of the locals cafés. She lives with her husband John and her 22 year old son.
• Typical Day
– 7.45: Cup of Coffee
– 11.00: Sausage Roll/ 2 Biscuits and Cup of Tea
– 13:00: Sandwich with Ham, Cheese and Tomato or Chicken and Coleslaw
– 15:00: Yoghurt/ Crisps/ 2 Biscuits and Cup of Tea
– 18:00: Meat, Potatoes and Veg and Dessert (Rice Pudding/Stewed Apples/Apple Tart)
– 22:00: Cup of Tea and Toast
•
•
•
Calculate Catherine’s BMI. What other questions would you ask her?
Comment on her current diet
Discuss the care you are going to give Catherine. Consider barriers to change, short
term and long term goals
Plan out a suggested day's menu for Catherine
•
National Weight Control Registry
(USA)
• http://www.nwcr.ws
• Members have lost average of 30kg (range 13 – 136kg) & kept
it off for 5.5 years
• 45% did it alone & 55% had help of a programme
• Most report low calorie, low-fat diet with high levels of
activity:
– 78% eat breakfast every day
– 75% weigh themselves at least once per week
– 62% watch less than 10 hrs TV per week
– 90% exercise for about 1 hour a day
Exercise and Diet
• Increased physical activity is effective in producing a modest weight loss.
• Evidence suggested that diet alone is more effective than exercise alone.
Exercise for overweight or obesity. Cochrane Database of Systematic
Reviews 2009, Issue 4
• When compared with no treatment, exercise resulted in small weight
losses across studies
• Documented that exercise combined with diet changes resulted in a
greater weight reduction than diet alone
• Increasing exercise intensity increased the magnitude of weight loss
• Exercise is associated with improved cardiovascular disease risk factors
even if no weight is lost
• Evidence also suggests combined exercise and diet interventions are
better than diet‐only interventions for long‐term weight loss in adults (Wu
et al, 2009)
Summary: Weight Management
Offer multi-component interventions to encourage:
• – increased physical activity
• – improved eating behaviour
• – healthy eating
– Health benefits to improving diet even if no weight los weight
– Individually tailored to food preferences and allow for flexible
approaches to reducing calorie intake
– Avoid overly restrictive and nutritionally unbalanced diets because
they are ineffective in the long term and can be harmful
– Longer term the idea is to move towards eating a balanced diet,
consistent with general healthy eating guidelines
Summary: Weight Management
•
Drug treatment
– Consider only after dietary, exercise and behavioural
approaches have been started and evaluated for
effectiveness – i.e. individual has returned for review(s) &
weight checks
– Consider for patients who have not reached their target
weight loss or have reached a plateau on dietary, activity
and behavioural changes alone
Summary: Weight Management
•
•
•
•
•
•
Realistic targets for weight loss, usually
– maximum weekly weight loss of 0.5–1 kg.
– aim to lose 5–10% of original weight.
Discuss the importance of developing skills for both losing weight and maintaining lost
weight (the typical weight loss phase is 6–9 months of treatment – then starts maintenance)
For sustainable weight loss, recommend diets that have a 500kcal/day deficit (that is, they
contain 500kcal less than the person needs to stay the same weight) or reduce calories by
providing tailored dietary advice – e.g. portion control, fat reduction, high fat/sugar foods
reduction, increase fruit/veg
Low-calorie diets (1000–1600 kcal/day) may also be considered, but are less likely to be
nutritionally complete
Very-low-calorie diets (less than 1000 kcal/day) may be used for a maximum of 12 weeks
continuously, or intermittently with a low-calorie diet (for example for 2–4 days a week), if
the person is obese and has reached a plateau in weight loss
Any diet of less than 600kcal/day should be used only under clinical supervision
Weight-loss outcomes: a systematic review and meta-analysis
of weight-loss clinical trials with a minimum 1-year follow-up
Approach
Evidence
Reduced energy diet
5 – 8.5kg (5 – 9%) weight loss
in first 6 months when weight
plateaus*
Weight loss medications
Reduced energy diet + weight
loss medications
Advice only
minimal weight loss at any
time point
Exercise only
minimal weight loss at any
time point
Reduced-energy diet and
exercise
Moderate weight loss at6
months
*In studies extending to 48 months, a mean 3 to 6 kg (3% to 6%) of weight
loss was maintained with none of the groups experiencing weight regain
to baseline (Franz et al, 2007)
Useful Reading
•
•
Ahern AL, Olson AD, Aston LM, Jebb SA (2011). Weight watchers on prescription: an
observational study of weight change among adults referred to weight watchers by the
NHS. BMC Public Health. 11:434
Esfahani A, Wong JMW, Mirrahimi A, Villa CR, Kendall CWC (2011) The Application of the
Glycemic Index and Glycemic Load in Weight Loss: A Review of the Clinical Evidence. Life, 63(1): 7–
13
•
•
•
•
•
Franz, M. J., VanWormer, J.J., Crain, A.L., Boucher, J.L., Histon, T., Caplan, W., Bowman, J.D.,
Pronk, N.P. (2007) Weight-loss outcomes: a systematic review and meta-analysis of weightloss clinical trials with a minimum 1-year follow-up. Journal of the American Dietetic
Association. 107(10):1755-67.
Geissler, C. and Powers, H. (2011) Human Nutrition, 12th edn. Churchill Livingstone Elseveir.
pp 413-423.
Nordmann, A. J., Nordmann, A., Briel, M., Keller, U., Yancy, W. S., Brehm, B. J., Bucher, H. C.
(2011) Effects of low‐carbohydrate vs low‐fat diets on weight loss and cardiovascular risk
factors: a meta‐analysis of randomized controlled trials. Database of Abstracts of Reviews of
Effects, Issue 4.
Obesity The Policy Challenges (2005) The Report of the National Taskforce on Obesity.
<http://www.cllsp.ie/Libraries/National_Reports/National_Taskforce_on_Obesity.sflb.ashx>
Shaw, K. A., Gennat, H.C., O’Rourke, P. (2009) Exercise for overweight or obesity. Cochrane
Database of Systematic Reviews, Issue 4.
<http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003817.pub3/full>