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Publication HNFE-141PPopular Diets:If It Sounds Too Good to Be True, It Probably IsElena Serrano, Associate Professor, Human Nutrition, Foods and Exercise, Virginia TechShaun Riebl, Graduate Student, Human Nutrition, Foods and Exercise, Virginia TechIntroductionThe promotion of different “diets” or diet programshas become rampant in our modern society, with manymaking erroneous claims about weight loss and healthylifestyles. It can seem that each time you hop on thecomputer or catch the news a groundbreaking way toshed pounds and get the perfect body is being touted.Sometimes these “revolutionary” diet programs recommend eliminating specific foods or food groups whilecombining others and using “specially formulated supplements” to shed pounds, build muscle, and cleansethe body of harmful toxins. However, on closer inspection, these claims and recommendations are not backedup by quality scientific studies in humans, nor are theydeveloped by legitimate nutrition professionals (e.g.,registered dietitians).Unfortunately, no food or supplement will magicallytake off extra weight or improve your mood. Eatingmore of one food and none of another won’t supercharge your metabolism or melt away fat. There aren’tany quick fixes when attempting to lose weight, maintain a healthy body size, or prevent the onset of disease.Some of these popular diets and diet programs blameweight gain on hormones, blood type, or a specificfood. They encourage immediate weight loss, suggestspecific combinations of foods, restrict some foodswhile promoting others, do not allow flexibility, usecase studies or personal testimonials to validate theirclaims, and/or promote (or sometimes require) the purchase of a pill, shake, or formula.Important Questions to AskSo how can you tell if a diet is a fact or fraud? Askthese questions: Do sound, quality scientific trials (more than onestudy) done in humans align with the diet’s claims? Do the diet’s claims correspond with the DietaryGuidelines for Americans (available at 010/PolicyDoc/PolicyDoc.pdf)? What are the credentials of the diet’s developer orfounder? Are supplements and/or pills necessary for successon the diet? Are they necessary because certain foodsand/or food groups are considered taboo? Does the diet emphasize one food group over another?Is there a food that must be eaten daily or at eachmeal?www.ext.vt.eduProduced by Communications and Marketing, College of Agriculture and Life Sciences, Virginia Polytechnic Institute and State University, 2013Virginia Cooperative Extension programs and employment are open to all, regardless of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, genetic information, marital, family, or veteranstatus, or any other basis protected by law. An equal opportunity/affirmative action employer. Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University,and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; Jewel E. Hairston, Administrator, 1890 Extension Program, Virginia State, Petersburg.VT/1013/HNFE-141P

Does the diet start with extreme caloric restriction ora fast? Are dramatic, too-good-to-be-true results promisedover a short period of time? (A healthy and reasonableweight loss is about 1 to 2 pounds per week.) Does the diet highlight both the benefits and risksassociated with it? Are megadoses of specific nutrients, vitamins, orminerals required or recommended?While this list is not exhaustive, it can be used as abasis for assessing the appropriateness of popular diets.Overview of Popular DietsThe table that follows provides a summary of theclaims, pros, and cons of some popular diets. The listis not all-inclusive; however, it can be used as a reference. For further information or counsel on other diettrends, please consult a Virginia Cooperative Extensionfamily and consumer sciences agent. Contact information for local VCE offices can be found at www.ext.vt.edu/offices.www.ext.vt.edu2

DietAtkins dietDescriptionClaims Promisesbetter hearthealth, memoryfunction, andweight loss on adiet of low carbsthat is rich inprotein and fat.Foods to Avoid All foods withrefined sugars. Milk. White rice, flour,and pasta. Potatoes.OK Foods Meat, eggs,cheese, fish, oliveoil. Some wholegrains, fruits, andvegetables (afterfirst two weeks). By drastically Carbs (for thedecreasingfirst two weeks).carbs and eatingincreased proteinand fat will leadto good healthand preventdisease. 1 2-weekprogram oflow carbsand physicalactivity will helpattain health,peak fitness,and maximizewillpower toreach life goals.ProsCons Exercise in allphases. Increasedcholesterol. 1 2 weeks of mealplans. Constipation (fromlack of fiber) andbad breath (fromlack of carb intake,causing ketosis). Allows whatare typicallyconsidered“forbidden” or“cheat” foods (e.g.,cream, high fat,meat, butter). Recommendssupplementsbecause notgetting enoughnutrients fromfoods like fruitsand vegetablesand to preventdizziness, fatigue,and leg cramps. May promote heartdisease, strokes,and cancer. Very restrictive/limited. Less than minimalcarbs for brainfunction (i.e., 130grams per day). No scientificliterature to verifyclaims and mainlypersonal accounts(i.e., anecdotal)or testimonialsare used to justifyclaims of increasedenergy, betterconcentration,decreased cravings,increased mood,and decreaseddepressivesymptoms.www.ext.vt.edu3

Diet“BiggestLoser” dietDescriptionClaims Low-calorie dietbased on fruits,vegetables, leanprotein, andphysical activity. Will decreaseblood pressure,cholesterol,weight, andincrease energy.Foods to AvoidOK Foods White bread,regular pasta,potatoes. Fruit, vegetables. Refined sugarsand grains. Lean protein. Whole grains. Foods withoutadded sugars, fat,and salt. Healthy fats (e.g.,olive oil, canolaoil, flax seed oil,nuts, seeds).Pros Monitoring withdaily food logs. Monitoring ofportion sizes. Daily exercise.Cons May not beenough carbs forsome people. Inaccurate methodto estimate calorierequirements. Promotes 48-64 Many not beounces daily wateradequate caloriesintake.(e.g., 1,050 caloriesfor a 150-pound Fruit andperson).vegetablesrecommended Questionableover juice andcalcium intake.dried fruit. Whole grainswith specific fiberrecommendations. Support (social). Increased fiberintake. Small, frequentmeals.www.ext.vt.edu4

DietBlood typediet (“EatRight for YourBlood Type”)DescriptionClaimsFoods to Avoid Blood type Depends onaffects digestionblood type, butand some foodscan includeare dangerous ifchicken, beef,not right for yourpork, wheat,blood type.corn, lentils,grains, breads, If you eat thelegumes, wholewrong foods forwheat, andyour blood type,wheat germ.it can slow yourmetabolism,causeinflammation,bloating, anddiseases likecancer.OK Foods Depends onblood type, butcan include leanmeats, poultry,fish. Soy protein. Grains. Organicvegetables.Pros Fruit andvegetableconsumption. Lean sources ofprotein.Cons Very restrictive. No science to backit up. Not individualizedfor preferences orneeds. May lack dairy. Tofu. Dairy. Some foods actas poisons whileothers are “highlybeneficial” or“neutral.” Blood typeimpacts how youshould exercise.www.ext.vt.edu5

DietDetox dietsDescriptionClaims Removing toxinswill promotedecreasedweight andoptimal bodyfunctioningand boostmetabolism. Somerecommend“cleanses” viasupplementsand enemas.Foods to Avoid Varies accordingto diet. Typically dairy,eggs, grains(oats, corn,wheat).OK Foods Fruits andvegetables (afterinitial fast). Water.Pros Avoidance ofprocessed foodsand foods high insugar and fat.Cons No scientificevidence backingmethods used indiets; based ontestimonials. Promises a quickfix. Pork, beef,sausage. Supplementswith unknownor questionableingredients. Nuts, seeds, oils. Alcohol. Electrolyteimbalances. Typically startswith a fastfollowed byreintroductionof fruit andvegetables,water, andsupplements. May slowmetabolismbecause so low incalories. Fatigue, nausea,vomiting, bloating. Toxins stay in ourbodies, causingfatigue, digestiveproblems, andother healthproblems. Causes publicto think that ourbodies cannotproperly ridthemselves oftoxins. Decreased proteinintake. Unsupervised useof enemas.www.ext.vt.edu6

DietDescriptionClaimsFoods to AvoidGrapefruit diet Claims grapefruit All fruit excepthas an enzymegrapefruit.that, when eaten All grains.with fats andhigh-protein Corn, carrots,foods, increasesbeans, peas.fat burning,resulting in High-carb saladweight loss.dressing. 1 2-day planpromises a10-pound weightloss by eating1/2 grapefruitor specifiedamount of 100%grapefruit juicebefore eachmeal.OK FoodsPros Nonstarchy Promotes watervegetablesconsumption.(lettuces, Good amountbroccoli, bellof vitamin C andpeppers, zucchini,fiber.cucumbers). Salt. Cheese. Nuts. Some high-fatmeats (e.g.,bacon).Cons Rapid weight loss. Insufficientcalories. Limits grains andsome fruits. Meals may be easy Snacking only afterto prepare.dinner. Sufficient Limited amountsvegetables.of foods to choosefrom/lacks variety. Low-carb saladdressing. Meals are thesame each day ofthe diet, differingonly in the type/source of proteineaten at lunchand dinner.www.ext.vt.edu7

DietJenny CraigDescriptionClaimsFoods to Avoid Three-level None.program todecrease weightand keep it offusing a balanceddiet and regularphysical activity. Starts withprepackagedmeals withultimate goal ofhaving peoplepurchase andprepare mealsthemselves.OK Foods All foods inmoderation withemphasis onfruits, vegetables,whole grains,low-fat dairy,unlimitednonstarchyvegetables.ProsCons Certifiedprofessionals“advise” theprogram. Questionableabout learningportion sizesbecause it’s hard tocompare real foods Teaches portionto the portionssize, meal planningin prepackagedand preparation,meals.and how to dealwith eating out. Support staff notnecessarily dietetic Dedicatedprofessionals.to weightmaintenance,addressingbehavioral aspectof foods, andexercise. Extensive support.www.ext.vt.edu8

DietDescriptionClaimsMediterranean Not a diet but away of life thatdietFoods to AvoidOK Foods Saturatedfat, sodium,sweets, meat(not necessarilyavoid them, butlimit to smallamounts). Fruits, vegetables,beans, wholegrains, extravirgin olive oil,yogurt, fish,poultry, eggs,some cheese.provides amplehealthy fats andplant foods withregular physicalactivity that willimprove heart Processed foods.health anddecrease the risk Fried foods.of cardiovasculardisease, cancer,obesity, anddiabetes.Pros Includes healthyfats. Physical activity. Many antioxidants,minerals, vitamins.Cons Food preparation. Not necessarilyused for weightloss. Decreasedsaturated fat andadded sugars. Includes lifestyleaspect. Palatable (tastesgood). Some studiesshow decreasedtotal cholesterol,triglycerides,blood pressure,and LDLcholesterol;increased HDLcholesterol. Decreased intakeof refined grains,high-fat dairy, andred meat.www.ext.vt.edu9