Weight loss

More than $60 billion spent annually on weight loss programs and products.

Individuals successful at achieving 6-12 or more months are physically more active than those who fail to maintain their weight loss.

Programs involving diet, exercise and behavior changes result in initial weight losses of approximately 10%.

The therapeutic effect of losing weight is proportional to the relative decrease in body weight: 5 to 10% weight loss and people with type two diabetes improves glycemic control, 15 to 25% weight loss can achieve diabetes remission.

With the advent of glucagon like peptide-1 inhibitors established a new era in the pharmacological therapy of obesity with mean weight loss of 15 to 25% at one to 1.5 years.

Intentional weight loss in obesity decreases body fat, but also decreases fat-free mass.

Skeletal muscle mass accounts with about 50% of fat free mass whereas the remainder of fat free mass is composed of the fat free mass of other fluids, organs, and body tissues.

The decrease in fat-free mass induced by weight loss and people with obesity represents about 25% of total weight loss and is influenced by initial body composition and total weight loss.

There is an inverse relationship between initial body fat mass and the proportion of weight loss from fat from fat free mass explains why men who generally have less body fat and more free fat than women usually have greater proportional weight loss from fat free mass than women.

The decrease in skeletal muscle mass induced by weight loss is mediated by an increase in muscle protein breakdown not a decrease in muscle protein synthesis.

Decrease in fat free mass is primarily responsible for the decrease in  basal metabolic rate that occurs after weight loss.

Diets to promote weight loss are divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie.

No one dietary intervention has proven superior for weight loss, as numerous diets are effective.

A meta-analysis of six randomized controlled trials found no difference between the main diet types: low calorie, low carbohydrate, and low fat, with a 2–4 kilogram weight loss in all studies.

For weight loss it is recommended 150 – 175 minutes of brisk walking or similar aerobic exercise per week.

Weight loss management is about changing behavior, with a lifelong goal commitment to healthy lifestyle habits.

Most people regain the weight they lose from dieting within one or two years, in part because the body adapts by slowing metabolism and burning fewer calories.

It is recommended that overweight and obese individuals lose 5-10% of their starting body weight within six months, which should be maintained for at least 12 months.

Setting personal weight loss targets can increase the rate of achieving at least 10% weight loss, compared with not setting goals.

Weight loss goals should be individualized to patient preference, body composition, and comorbidities.

A 5% weight loss may reduce systolic and diastolic blood pressure by 3 mmHg and 2 mmHg among those with hypertension, respectively.

A 5 to 10% body weight loss may decrease hemoglobin A1c by 0.621% among those with type two diabetes and can increase HDL cholesterol by 2 mg/dL

A 10 to 15% loss in weight may be required to improve other conditions such as; hepatic steatosis, obstructive sleep apnea.

Weight loss beyond 15% is associated with low rates of all cause mortality.

Among those who undergo bariatric surgery, and greater weight loss is associated with improve quality of life.

Physical activity alone, in the absence of caloric restriction, is unlikely to lead to substantial weight loss.

Individuals  who were not used to regular, intensive exercise are more likely to increase their caloric consumption, once they started a more intense exercising program than those who were already used to regular exercise.

Dietary restriction alone is unlikely to provide sustained results in the absence of a regular exercise program or increase in physical activity.

Weight loss is recommended for patients with type two diabetes and moderate weight loss of 5 to 10% can improve glycemic control and other cardiometabolic risk factors and comorbidities.

Weight loss of just 5% through a combination of dietary restrictions, and behavioral therapy is effective in achieving better glycemic control and preventing diabetes.

Effective as reducing obstructive sleep apnea.

Studies show that reducing weight by even only 7 percent can reduce the chances of developing diabetes by 58 percent.

As little as 3% weight loss improves glycemic control in diabetes.

Achieving and maintaining weight loss is difficult because of multiple obesity related hormonal, metabolic, and neuronal adaptations favoring weight gain.

Weight regain is common in lifestyle therapy in patients with obesity and is also common after weight loss indced by anti-obesity medications if pharmacotherapy is stopped.

Patients with diabetes often experience reduced response to weight management pharmacotherapy compared to individuals without diabetes.

The 0.5 kg per week of weight loss follows the Centers for Disease Control and Prevention (CDC) recommendation of gradual and steady weight loss of 1–2 lbs per week for long-term success 

Only one in six obese adults report ever having maintain weight loss of at least 10% for one year.

Poor long-term outcome of weight loss diets relates to the behavior, in that motivation to adhere restrictive regimens diminishes with time.

Evidence-based obesity treatment requires a combination of interventions with five major categories: behavioral intervention, nutrition, physical activity, pharmacotherapy, and bariatric procedures.

Psychological support toward identifying barriers to change, monitoring barriers, problem-solving, strategizing, reinforcement are important components of weight loss programs.

It is important to manage depression, and anxiety which can compromise adherence to patient’s lifestyle changes.

Patients should be screened for sleep disturbances and stress, and appropriate management offered.

An alternative explanation for poor long-term weight-loss elicits biological adaptations specifically a decline in energy expenditure known as adaptive thermogenesis and than an increase in hunger promoting weight gain.

In obese older individuals without heart failure diet calorie restriction and weight loss improves left ventricular hypertrophy, improves exercise capacity, improves glucose, lipids, blood pressure control, decreases inflammatory markers, improves body composition and skeletal muscle function.

Weight loss improves the quality of remaining muscle by decreasing intramyocellular and intermuscular triglycerides and increasing muscle insulin sensitivity

For weight loss it is recommended 150 – 175 minutes of brisk walking or similar aerobic exercise per week.

Most diet programs result in a regaining of about one third of weight loss during the following year and typically are back to baseline by 3-5 years.

There is a direct relationship between dietary adherence and weight loss, regardless of dietary treatments.

Dietary composition effects energy expenditure directly by virtue of macronutrient differences or indirectly through hormonal responses to diet that regulate metabolic pathways.

The standard unit of measure for calories is kilocalories or kilojoules per 100 g of food or beverage consumed.

The optimal diet for weight loss, whether low fat, low carbohydrate, or high protein diet remains debated.

Frequent self weighing, improves, weight loss and weight loss maintenance.

No preferred diet exist for achieving sustained weight loss.

Weight loss can be achieved regardless of the macronutrient composition with various calorie-restricted diets,as long as it is it adhered to the hypocaloric caloric dietary plan.

Low-fat and fat-free foods are not necessarily low in calories, since they may contain sugar.

Individuals that maintain weight loss have excess energy expenditures of 2200 kcal-2800 cal/wk.

Reduced calorie diets divided into very low-less than 800 kcal daily, low-800-1500 kcal a day and moderate-approximately 500 kcal less than typical daily diet.

Recommended as a 2092-kj(500 kcal) daily deficit leading to a .45 kg per week weight loss.

A deficit of 500 calories per day can achieve a 1 pound weight loss weekly, because a net reduction of 3500 calories is required to lose 1 pound of body weight (Bouchard C etal).

For weight loss it is recommended a daily caloric deficit of 500 – 750 kilocalories, which translates to a caloric intake of 1200 – 1500 kilocalories per day for most women and is expected to result in an average weight loss of 0.5 – .75 kg per week.

Losing weight slowly and steadily provides no advantage in maintaining weight loss compared with very low calorie diets that work quickly (Purcell K et al).

Weight loss of 5-10% is associated with reduction in diabetes and cardiovascular disease (Klein S et al, Knowler WC et al).

Weight loss of 5% is considered clinically meaningful.

Energy content per kg change of body fat is 39.5MJ and 7.6MJ for a kg of lean mass.

To lose the same mass of fat as lean tissue requires about a 5 fold greater deficit in net energy.

Less energy is stored in lean tissue than in body fat.

Lean tissue is more energetically expensive to maintain than is body fat and contributes more to the body’s overall energy expenditure rate.

Weight loss typically plateaus after six months due to metabolic adaptation and hormonal changes that contribute to decreased adherence.

Metabolic adaptation usually slows after 12 months.

Adjuncts to effective dieting includes eating breakfast, increasing dietary fiber and utilizing meal replacements and involving dieticians in programs.

Recommended to have a dietary fat intake limited to less than 30% of total calories, although effectiveness of such diets remain controversial.

Regardless of shifts in total proteins, carbohydrates or fat intake, successful weight loss requires adherence to a diet that is reduced in total energy intake.

Behaviorally, weight loss involves reducing the total number of calories consumed to achieve an energy deficit over time.

Energy dense foods and beverages have more energy per unit weight of a food compared with non-energy dense foods such as fruits and vegetables that contain more water or fiber.

Energy density and increased portion size influence excessive energy intake and increased risk for being overweight.

Lifestyle Heart Trial of intense diet counseling, exercise, stress management in patients with coronary artery disease and a 7% fat caloric intake resulted in a weight loss of 24 lb after 1 year, and a 5 year decrease progression rate of coronary heart disease.

Most, but not all, trials indicate that in the first 6 months randomization between low carbohydrate and low fat diets, that the low carbohydrate diet yields significantly more weight loss in the first 6 months: at twelve months the differences were not significant.

In a comparison of weight loss diets with randomization to the Atkins, Slim-Fast, Weight Watchers or Rosemary Conley or control group the 6 month analysis that all diets led t significant and similar losses of body fat and to reductions in blood pressure (Truby).

Substitution of protein for carbohydrates in calorie restricted diets result in more weight loss with the high protein diet.

Complications progress in severity from impaired immune function and delayed wound healing to profound weakness, pneumonia, and a 50% mortality rate as weight loss proceeds from 10% to 30% of the patient’s baseline status.

Associated with improved lipid levels, blood pressure, and blood glucose metabolism.

In a European study of adults and a low-calorie diet phase randomized into one of five maintenance diets, a modest decrease in protein content and modest reduction in glycemic index lead to improvement in study completion and maintenance of weight loss(Larsen TM et al It).

Reduction in weight as little as 5-10% may be sufficient for modification of waist circumference, blood pressure, glucose levels, triglycerides, HDL level and circulating cytochrome.

Macronutrient composition of the diet does not affect weight loss, but may affect cardio metabolic risk.

Low-fat diets may lead to a greater Improvement in low density lipoprotein cholesterol levels, whereas low carbohydrate diet may result in greater improvement in triglyceride and high-density lipoprotein cholesterol levels: the differences are small, and health benefits are mainly those that result from calorie restriction induced weight loss.

Comparison of low carbohydrate (Atkins), high protein, low carbohydrate (Zone), very low fat (Ornish), and Weight Watchers diets at one year reveal no significant differences in weight loss.

In a randomized study comparing Atkins carbohydrate restricted diet, Zone diet with 40% carbohydrates, 30% fat, 30% protein, Weight Watchers diet with calorie restriction or the Ornish diet with fat restriction: at 1 year the mean weight loss was the same for all 4 groups (Dansiger).

In a randomized trial comparing the Atkins, Zone, Weight Watchers and Ornish diet in healthy women 20-50 years of age the Atkins diet resulted in more weight loss than the Zone diet and no other significant differences in weight loss among the diets (Gardner).

Associated with improvement of risk factors for disease, however, controlled studies to show that weight loss reduces mortality is lacking.

Most observational studies indicate that weight loss is associated with increased cardiovascular and other cause death rates, probably due to the inclusion of patients who had conditions that lead to their deaths.

Weight loss has been shown to be paradoxically associated with an increased incidence of cardiovascular events, and even in participants who were overweight or obese at baseline (Christou NV et al).

Swedish Obese Subjects study of bariatric surgery demonstrated long term weight loss and decreased overall mortality.

Increase in physical activity alone, without decreased intake of calories is associated with only modest weight reduction.

Jogging the equivalent of 20 miles a week without caloric restriction resulted in a weight loss of 2.9 kg in 8 months (Slentz).

Physical activity without calorie restriction can reduce visceral adipose tissue and improves insulin resistance.

Weight loss effect increases insulin sensitivity is proportional to the degree of weight loss, and can range from 20% to 200%.

Increased physical activity combined with caloric restriction results in more weight reduction and more favorable changes in body composition than diet or physical activity alone (Miller)

A combination of diet and aerobic exercise is associated with increases in HDL, reductions in triglyceride levels and blood pressure compared t diet alone (Wood).

Eating large portions of fruits and vegetables is not an effective weight-loss strategy (Kaiser KA et al).

Data from the Nurses’ Health Studies and the Health Professional’s Follow-up Study show that women and men who increased their intakes of fruits and vegetables over a 24-year period are more likely to have lost weight than those who ate the same amount or those who decreased their intake. 

While exercise combined with healthy eating choices is the most effective for weight loss.

Use smaller plates:

Using bigger plates can result in you serving 9% to 31% bigger portions than you usually would, leading to an increase in weight gain.

Dinner plate sizes have increased on average by 23% since 1900.

Studies show individuals offered a larger portion increase their calorie intake by 30% compared to those offered a smaller portion.

Individuals who used their smart scales the most lose more weight.

More or less 40% of weight lost by any means is regained in 1 year, and close on 100% of weight lost is regained after 5 years.

Avoid mid-morning snacking: women who do not snack between breakfast and lunch lose on average 4% more body weight in comparison to mid-morning snackers.

Waiting too long between meals can impair weight loss efforts as snacking can help manage hunger better and help in making healthier choices at the next meal.

Choosing healthy snacks is important.

Avoiding junk food snacks and snack instead on nuts and low calorie fruit such as apples, which contain a soluble fiber called pectin.

Pectin promotes the feeling of fullness, and helps to slow down digestion.

Not snacking before lunchtime and always keeping healthy snacks on hand to avoid the temptation of indulging in junk food snacks.

Six drugs approved afor weight loss: Diethylpropion (Tenuate), Orlistat (Xenical, Alli), Phentermine (Ionamin, Fastin Celltech), and Sibutramine (Meridia), liraglutide, and  Semaglutide.

Sibutramine may be associated with increased cardiovascular events: SCOUT study(Subitramine Cardiovascular Morbidity/Mortality Outcomes in Overweight or Obese Subjects at Risk of Cardiovascular Event) of 10,000 individuals aged 55 years or older with obesity, type II diabetes or heart disease, adverse cardiovascular events were seen in 11.4% of subitramine patients and 10% of placebo patients (European Medicines Agency).

Sibutramine removed from the market because of myocardial infarction and stroke.

Diethylpropion is a schedule IV controlled substance with a sympathomimetic mechanism.

Diethylpropion can result in dry mouth, insomnia, dizziness, increased blood pressure and increased heart rate.

Diethylpropion use requires monitoring of blood pressure.

Diethylpropion excreted by the kidneys.

Diethylpropion dose is 25 mg tid or 75 mg controlled release daily.

Liraglutide 3 mg daily subcutaneous as an adjunct to diet and exercise is associated with reduced weight and improved metabolic control (Pi-Sunyer et al).

Weight loss in obese individuals improves psychological states including mood.

Associated with advanced malignant disease involves fat and lean body mass especially skeletal muscle.

Phentermine/Topiramate ER (Qsymia) one of the most effective drugs available for weight loss.

The combination of bupropion and naltrexone (Contrave) for weight loss is associated with nausea and neuropsychiatric reactions.

Pharmacotherapy plus counseling in obesity can nearly double the weight loss of either alone.

The metabolic benefits of gastric bypass surgery and diet are similar and are apparently due to weight loss itself, with no ads clinically important effects independent of weight loss.

A randomized, cross-over trial of more than 60 overweight individuals indicates a low-fat vegan diet was more effective than a Mediterranean diet for inducing weight loss and lowering cholesterol levels.


A low-fat vegan diet appeared to be a more effective approach than adherence to a Mediterranean diet for inducing weight loss and improving cholesterol in this patient population.


Upon analysis, investigators found overall weight changes of 0.0 kg for the Mediterranean diet and -6.0 kg with the low-fat vegan diet.


Semaglutide and other GLP-1 (Glucagon like peptide 1) agents provide weight loss by improved appetite control, reduced energy intake via the hypothalamus and area post strema of the brain.


Among adults with overweight or obesity completing a 20 week run in ofsubcutaneous semaglutide results and continued weight loss.

Findings from a multi-center, international clinical trial showed that semaglutide reduced cardiovascular events by 20% in adults with overweight or obesity and established cardiovascular disease who don’t have diabetes. 

In the trial, patients treated with semaglutide lost an average of 9.4% of their body weight and experienced improvements in other risk factors for cardiovascular disease. 

In the trial, for patients with preexisting cardiovascular disease and overweight or obesity but without diabetes, weekly injections of semaglutide at a dose of 2.4 mg was superior to placebo in reducing the risk of death from cardiovascular causes, nonfatal heart attack, or nonfatal stroke over an average follow-up of 40 months. 

High body-mass index (BMI) is estimated to have accounted for 4 million deaths globally in 2015, more than two thirds of which were caused by cardiovascular diseases.  

Semaglutide, a GLP-1 receptor agonist medication initially approved and most frequently prescribed for adults with type 2 diabetes, was also FDA-approved in 2021 for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity. 

Weight loss effects of semaglutide appear to occur primarily through appetite suppression, this drug has other actions which may reduce cardiovascular risk, including improvements in glucose levels, decreases in blood pressure and cholesterol levels and reductions in inflammation, and beneficial effects on heart muscle and blood vessels.  

In the SELECT trial, over 17,000 patients in 41 countries who had previously experienced a heart attack, stroke and/or had peripheral artery disease were enrolled and followed for an average of 40 months after being randomly assigned to receive once weekly injections of semaglutide 2.4 mg or placebo.  

Death from a cardiovascular event, nonfatal myocardial infarction, or nonfatal stroke occurred during the trial in 6.5% of patients who were treated with semaglutide versus 8.0% of patients who received placebo -a 20% reduction in relative risk by semaglutide. 

Risk reductions were similar in men and women and across different ethnicities, patient ages and baseline levels of bodyweight. 

More patients discontinued semaglutide (16.6%) than placebo (8.2%), due primarily to gastrointestinal symptoms including nausea and diarrhea. 

There was a slightly higher rate of gallbladder disorders in the semaglutide vs. placebo group (2.8% vs. 2.3%, respectively), which has also been previously reported in other studies with GLP-1 agents. 

Importantly, semaglutide was not associated with higher risks for severe gastrointestinal disorders, pancreatitis, psychiatric disorders or kidney injury. 

The effects of semaglutide on primary prevention of cardiovascular events in persons with overweight or obesity, but without previous cardiovascular disease, were not studied. 


Combining exercise and liraglutide therapy improves healthy weight loss maintenance more than either treatment alone.


There is not enough data to determine which, if any, herb supplements and dosages are safe and effective for weight loss.


Those individuals who eat a breakfast higher in fiber tend to eat less at their next meal.


Individuals who have more protein at breakfast feel more full than those consuming less protein at breakfast.


When cutting calories, those who eat most of their calories in the morning tend to lose more weight than those who eat most of their calories in the evening.


Diet-induced thermogenesis, refers to  the amount of heat your body produces in response to eating. 


The body puts out over twice as much heat after eating breakfast than they did after eating dinner.


This suggests greater thermogenesis at breakfast be one of the reasons people lost more weight eating the majority of their calories at breakfast.

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