Weight Loss and Maintenance
Results of the National Health and Nutrition
Examination Survey (NHANES), 1999, indicate that an estimated
61% of US adults are either overweight or obese [1].
The definition of obesity is generally determined by use of the
Body Mass
Index (BMI) which is calculated as the weight (kg)/height
(m2). A value of >30 is defined as obesity and a value >25
is defined as overweight [2].
Other measures to define obesity include: waist circumference
(>40 inches for men, >35 inches for women), percentage of
body fat, and comparison with "ideal" body weight tables
from insurance companies.
A recent consensus conference was published to help health professionals
address this public health problem [3].
There is a great deal of data on the short term effect of diets but little
data on the long term success of weight loss and factors that are associated
with successful weight loss. The three factors that are important in weight
loss include: dietary changes, increased exercise, and development of
new behavioral skills to support these changes. A current study, the
National Weight Control Registry, is monitoring persons who have been
successful at weight loss, defined as having lost >30 lbs and kept
it off for 2 years or more. The study has tentatively identified three
factors associated with this success: 1) change in diet, usually to a
lower fat diet, 2) increase in physical activity to ~ 2,500 kcal/week,
and 3) a "regimentation" of the eating events or plan [4].
Popularized diet plans are constantly emerging and have recently focused
on the proportion of the macronutrients (protein, carbohydrate and fat)
that are most conducive to weight loss. Few studies are available that
have systematically investigated the role of amount and type of macronutrients
and their relationship to weight loss or weight maintenance. Current popularized
diets include: 1) Atkins diet- high in fat and protein,
and low in carbohydrate from all sources, which is suppose to keep serum
insulin levels low; 2) South Beach diet -a modified Atkins-like diet that
encourages fruits and vegetables that contain carbohydrates, are still
higher in total fat but moderate in saturated fat and high in protein;
3) Zone diet-a diet with a ratio of 40:30:30 of carbohydrate:
protein: fat which concentrates on fruits, vegetables, whole grains and
legumes as the best sources of carbohydrates and lean proteins with an
emphasis on intake of n-3 fatty acids. This diet is cited to maintain
a balance between insulin/glucagons, which is conducive to weight loss
and maintenance; 4) Sugar Busters Diet- removal of
carbohydrates that are rapidly absorbed and increase serum insulin (and
are generally foods with a high glycemic index),
5) WeightWatchers Diet- a balanced diet of all three
macronutrients with control of portion size by assigning a number score
to foods and staying within oneís allotted number for weight loss, and
6) Pritikin or Ornish Diet- these diets stress a high
carbohydrate diet that comes from carbohydrate foods that are high in
fiber, with a low glycemic index and is a diet
very low in fat (~10% of calories). Carbohydrates come from whole fruits,
vegetables, whole grains and legumes with little processed foods and resembles
dietary intakes of non-industrialized countries.
There is currently no data to suggest that weight loss
is due to a "special" proportion of macronutrients but
instead that some dietary patterns are easier to maintain at a
lower caloric level which is the ultimate reason for the weight
loss observed. Both amount and type of each of the macronutrients
needs to be considered in designing studies to determine observed
differences in weight loss on the different diets. See also research
articles evaluating popular diets.
Counseling of patients for weight loss usually involves addressing
reducing the fat content of the diet (mostly saturated fat since
it is a risk factor for CVD) with its higher caloric density of
9 kcalories /g versus 4 kcalories/g for protein and carbohydrates,
increasing satiety by increasing the fiber content of the diet,
decreasing the glycemic index of the diet since a high glycemic
load diet appears to increase caloric intake and eating events,
and increased intake of fruits and vegetables because of their
high nutrients density, low glycemic index, and high fiber content
[5].
Increased exercise is also important in order to enhance caloric
expenditure and maintain oneís lean body (muscle) mass which determines
a personís caloric needs in order to lose fat weight and not muscle
weight.
Glycemic Index Definition:
- Glycemic Index (GI): An index comparing the effect of 50g of carbohydrate from a food to raise blood sugar using 50g of white bread or 50g of glucose as the standard of comparison, set at 100.
- Glycemic Load (GL): Used to determine the total effect of the GI of a total meal or the day. The GI of the food is multiplied by the gram of carbohydrate in the food consumed to determine the glycemic load of that meal or the day. This helps to adjust for the fact that the amount of carbohydrate in the different foods and in a usual serving size varies considerably and that we seldom take in 50g of carbohydrate from most foods.
Resources and Links - Diet Interventions
- Food
and Nutrition Information Center
USDA, National Agricultural Library
Information gateway with numerous links to consumer oriented web resources on:- Childhood Obesity
- Treatment Prevention Guidelines and Background
- Evaluating Weight Control Programs
- Practical On-line Weight Control Assistance
- Non-diet Approach
- Sample Weight Loss Clinic Programs
- Lahey Clinic - Obesity Clinic
- Tufts-NEMC Weight Loss Program - Obesity Consult Center
- Physicians
Weight Loss Centers
- WeightWatchers
Philosophy and program from website:- Believe dieting is one part of long-term weight management.
- Motto: "Eat foods you like and lose weight."
- Organized group meetings provide motivation, mutual support and encouragement, and instruction.
- Winning Points plan: foods have POINTS® value based on number of calories, grams of fat, and grams of fiber. Each person has a Daily POINTS® range and chooses foods to eat within that range. Program states that staying within the Daily POINTS® range produces weight loss.
- Meal Plans (Regular, Higher-Carbohydrate, Higher-Protein
and Vegetarian). Seven-day daily menus customized to person's
daily POINTS® range.
- Atkins Diet
- Philosophy includes four-phase eating plan with vitamin and mineral supplementation and regular exercise. Also based on nutritional principles to achieve goals: weight loss, weight maintenance, good health, disease prevention.
- "Atkins restricts processed/refined carbohydrates ..., such as high-sugar foods, breads, pasta, cereal and starchy vegetables. Core vitanutrient supplementation includes a full-spectrum multivitamin and an essential oils/fatty acid formula."
- Four phases (quoted from the Atkins Center website):
- "Phase 1: Induction - Restrict carbohydrate consumption to 20 grams each day, obtaining carbohydrate primarily from salad and other non-starchy vegetables.
- Phase 2: Ongoing Weight Loss (OWL) - Add carbohydrate, in the form of nutrient-dense and fiber-rich foods, by increasing to 25 grams daily the first week, 30 grams daily the next week and so on until weight loss stops. Then subtract 5 grams of carbohydrate from your daily intake so that you continue sustained, moderate weight loss.
- Phase 3: Pre-Maintenance - Make the transition from weight loss to weight maintenance by increasing the daily carbohydrate intake in 10-gram increments each week so long as very gradual weight loss is maintained.
- Phase 4: Lifetime Maintenance - Select
from a wide variety of foods while controlling carbohydrate
intake to ensure weight maintenance and a sense of well-being.
This lifestyle is the foundation for a lifetime of better
health."
- Zone
Diet
OmegaZone™ Dietary Program (quoted from Zone Diet website) "is based upon:- Consistent insulin control coupled with the supplementation of high-dose fish oil in order to modulate the synthesis of arachidonic acid.
- Insulin control is achieved by balancing protein and carbohydrate at each meal. The insulin-control component ... can be described as a moderate-carbohydrate, moderate-protein, and moderate-fat dietary program.
- The maximum amount of low-fat protein at any one meal should be no bigger than the size and thickness of the palm of the hand (this is approximately 3 oz. for females and 4 oz. for males).
- The majority of carbohydrates should come from vegetables and fruits, with starches (such bread, potatoes, rice, and pasta) used sparingly as condiments.
- Finally, most of the fat should consist of heart healthy monounsaturated fat.
- Unlike high-protein diets (that induce ketosis) or high-carbohydrate diets (that elevate insulin levels), the insulin control component of the OmegaZone dietary program is based on balance and moderation at each meal.
- The other component ... is supplementation with high-dose fish oil."
- Sugar
Busters!® Diet
- Very Low Fat
- Dean
Ornish, M.D.'s Lifestyle Program
Low-fat, plant-based diet (from WebMD website):- Fruits, vegetables, whole grains, beans, and soy products in their natural forms.
- Moderate quantities of egg whites and nonfat dairy or soy products.
- Small amounts of sugar and white flour.
- "These foods ... are low in substances that are harmful and are rich in literally hundreds of substances that may be protective against heart disease and many other illnesses."
- Recommended Nutrition Supplements: one per day multivitamin with vitamin B12 (without iron unless of childbearing age); omega-3 fatty acid source, men (3 grams fish oil capsules) and women (2 grams fish oil capsules and 1 gram flaxseed oil capsules); one serving per day full-fat soy product, defined as a soy food that contains 3-6 grams of fat from naturally occurring fat derived from the soybean. No added oil or fat should be added to the soy food from the manufacturer. Soy supplements are not recommended. Soy powders do not meet the definition for a full-fat soy product.
- Optional Nutrition Supplements: vitamin C (1-3 grams/day),
vitamin E (100-400 IU/day. Check with a doctor if taking
statin medications.), beta-carotene: food sources only
(10,000-20,000 IU/day), selenium (100-200 mcg/day), folic
acid (400-1000 ug/day).
- Terry
Shintani, M.D.
(Information from fatfree.com website, an internet partner of the International Vegetarian Union)- Daily
- Whole Grains: 8-13 servings
- Vegetables: 3-5 servings
- Fruit: 2-4 servings
- Non-Dairy Calcium Foods: 2-3 servings
- Non-Cholesterol Protein/Iron Foods: 2-3 servings
- Optional or Special Occasion
- Dairy
- Fish/Poultry/Meat
- Fats/Oils/Sugar
- Daily
- John
McDougall, M.D.
(Information from fatfree.com website, an internet partner of the International Vegetarian Union)
Twelve-Day Diet:- During diet do not eat/drink: Dairy products, eggs, meat, poultry, fish, vegetable oils, mayonnaise, white (refined) flour, coconut, refined and sugar-coated cereals, coffee (regular or decaf), black teas, colas and un-colas.
- After 12 days may eat in small amounts: Soybeans and soybean derivatives (tofu, tempeh, miso, high-fat soy milk), nuts and nut butters, seeds, olives, avocado.
- Eat: Whole grains, whole-grain cereals; squash; root, green, and yellow vegetables; legumes; fruit (two servings/day limit); sugar/salt/spices used sparingly.
- Avoid: All red meat, poultry, fish, dairy products, oil in any form, eggs, nuts, seeds, avocados, olives, soybean products, dried fruit and fruit juices, flour products.
- Gabe Mirkin,
M.D.
From www.fatfree.com/diets/mirkin.html:- No more than 20 grams of fat per day
- Focus on low-fat/high fiber foods
- Eat up to 5 servings of low-fat, low-fiber foods
http://www.library.tufts.edu/ezproxy/ezproxy.asp?LOCATION=http://dx.doi.org/10.1016/S0002-9343(00)00494-0
- Research Articles
- Atkins, SugarBusters!®, Zone, Ornish, etc.: Anderson JW. Konz EC. Jenkins DJ. Health advantages and disadvantages of weight-reducing diets: a computer analysis and critical review. Journal of the American College of Nutrition. 19(5):578-90, 2000 Oct. (HHSL Journal Stacks)
- Weight Watchers: Lowe MR. Miller-Kovach K. Phelan S. Weight-loss maintenance in overweight individuals one to five years following successful completion of a commercial weight loss program. International Journal of Obesity & Related Metabolic Disorders. 25(3):325-31, 2001 Mar. (HHSL Journal Stacks)
- Weight Watchers: Heshka S. et al. Self-help weight loss versus a structured commercial program after 26 weeks: a randomized controlled study. American Journal of Medicine. 109(4):282-7 Sep.
- Atkins, Zone: Landers P. et al. Effect of weight loss plans on body composition and diet duration. Journal - Oklahoma State Medical Association. 95(5):329-31, 2002 May.
- Zone: Jarvis M. McNaughton L. Seddon A. Thompson D. The acute 1-week effects of the Zone diet on body composition, blood lipid levels, and performance in recreational endurance athletes. Journal of Strength & Conditioning Research. 16(1):50-7, 2002 Feb.
- Low Fat: Pirozzo, S. Summerbell, C. Cameron, C. Glasziou, P. Advice on low-fat diets for obesity. Cochrane Metabolic and Endocrine Disorders Group Cochrane Database of Systematic Reviews. Issue 3, 2002.
- Low Fat: The role of low-fat diets in body weight control: a meta-analysis of ad libitum dietary intervention studies. Database of Abstracts of Reviews of Effectiveness. Issue 4, December 2002.
Resources and Links - Conditions
-
Childhood Obesity
MayoClinic.com - Overweight
and Obesity
National Center for Chronic Disease Prevention and Health Promotion - Shape Up America!
“The purpose of Shape Up America! is to educate the public on the importance of the achievement and maintenance of a healthy body weight through the adoption of increased physical activity and healthy eating.” - Understanding
Adult Obesity
National Institute of Diabetes & Digestive & Kidney Diseases
NCCAM