“If you follow this diet, you’re going tolose weight, you’re going to behealthy and you’re going to be able

to improve your quality of life … it’s scien-tifically based, but it’s also common sense.”

Another diet guru flogging their snake-oil prescription for the servings of fat, carbo-hydrate, protein and other nutrients neededto be healthy and slim? No. This was TommyThompson, then US Secretary of Health,speaking on 12 January at the release ofUncle Sam’s very own diet book, DietaryGuidelines for Americans 2005.

The guidelines, revised every five years,inevitably amount to a compromise betweennutrition advocates and the food and agri-culture lobbies.Yet this time they largely havepleased even staunch critics of governmentfood policy. “They look to me like thestrongest dietary guidelines yet produced,”said Michael Jacobson,who heads the Centerfor Science in the Public Interest, a nutritionadvocacy group in Washington DC,at a pressconference after the release.

But in the aftermath, a philosophicaldivide has emerged. On the one hand is theview, expressed by Thompson, that the gov-ernment’s role is to put out information aboutwhat constitutes healthy eating,but that it’s upto individuals whether they follow the advice.The other take is that the government must domore, not only to educate people about foodchoice, but to ensure a food supply that accu-rately reflects its own dietary advice.For thosewho take this view, the guidelines don’t go far

enough — and they say that buried in the fineprint are concessions to the food industry thatthreaten to weaken the impact of the advice.

The guidelines — a joint effort by theDepartment of Health and Human Services(DHHS) and US Department of Agriculture(USDA) — were first issued in 1980, andform a reference for US eating habits. Theyunderpin government nutritional policy andfederal food programmes, including schoolmeals. And they will be summarized graphi-cally in a new ‘food guidance system’, whichwill be released within weeks to replace the‘food pyramid’introduced in 1992.

Fat fightersPrevious guidelines focused on cutting con-sumption of the saturated fats that causechronic conditions such as heart disease.But the top priority now is to roll back theobesity epidemic that is causing a surge inconditions such as type-2 diabetes. Abouttwo-thirds of US adults are deemed over-weight or obese by the Centers for DiseaseControl and Prevention in Atlanta, Georgia.

Consequently, the biggest change in thenew guidelines is the emphasis on restoringenergy balance to people’s diets.The messageis that there is no getting round the laws ofthermodynamics. If your calorie intakeexceeds your energy output, you will gainweight. To this end, the guidelines advise aclose watch on calories and 30–60 minutes ofexercise most days of the week; 90 minutes toshed unwanted flab.

794 NATURE | VOL 433 | 24 FEBRUARY 2005 | www.nature.com/nature

Obesity is the maintarget in the US

government’s latestdietary guidelines. But

can this advice reallymake a difference?

Nature’s reporters siftthrough the heady mixof politics and scienceto get a taste of things

to come.

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That’s old hat to dieters, but the surprisethis time was the explicit statement that thehealthiest way to reduce calories is to avoidadded sugars, certain fats and alcohol, all ofwhich are high in calories but low in essentialnutrients. In the past, such a message hasbeen all but taboo. The previous guidelinessay only that added sugars may contribute toweight gain. And in January 2004, the Bushadministration lobbied against phrasing inthe World Health Organization’s dietaryadvice that urged people to eat fewer sugaryand other high-calorie foods.

To hammer its point home, the scientificadvisory committee behind the guidelinesturned to the concept of ‘discretionary cal-ories’: the number of junk-food calories youcan eat daily without gaining weight. A typi-cal sedentary person who burns 2,200 calo-ries per day needs to eat about 1,910 caloriesof healthy food to meet their basic nutritionalneeds.This leaves 290 calories for a treat,suchas beer and potato crisps with late-night TV.

The idea, say committee members, is toraise people’s consciousnessabout overeating withoutdenying them their favouritesnacks.Even a relatively mod-est reduction of between 50and 300 calories per daycould prevent most newcases of obesity, particularlyamong children.“If we couldachieve this it would be the major crowning achieve-ment of the guidelines,” saysAlice Lichtenstein, a cardio-vascular researcher at TuftsUniversity School of Medi-cine in Boston, Massachu-setts, who sat on the scientific committee forthe 2000 guidelines.

Taste of the futureAlso new this year is an emphasis on fibre-and nutrient-rich whole grains instead ofrefined grains, and a recommendation to eatnearly twice the quantity of fruit and vegeta-bles suggested in the 2000 version, as a way tolower the risk of certain cancers, type-2 dia-betes, stroke and obesity. And the guidelinesnow clearly distinguish between differenttypes of fat. Gone is the blanket low-fat creedof the past 20 years. In its place is advice toavoid saturated fats, which are found in redmeat, for example, and trans-fats, which areabundant in processed foods. At the sametime, moderate amounts of healthy fats, suchas olive oil, are recommended.

The stronger wording in the new guide-lines is partly the result of changes to thedrafting procedure that gave scientific advis-ers greater autonomy. In 2003, the DHHSand USDA appointed 13 nutrition scientiststo the Dietary Guidelines Advisory Commit-tee and asked them to compile a report fromthe latest scientific literature. Bureaucrats at

the two agencies then reviewed this report,published in the Federal Register in August2004, and considered comments from inter-ested parties. They drafted the guidelinesthemselves, and communications specialiststransformed them into the slick, 84-pagebrochures released in January.

Separating the two phases made the sci-entific basis of the guidelines more transpar-ent, says Janet King, chair of the committeeand a researcher at the Children’s HospitalOakland Research Institute in Oakland,California. In the past, the committee mem-bers had to write the actual guidelines,whichforced them to consider factors such as howeasy they were for a lay reader to understand.The previous committee spent ages, forexample, debating whether to advise peopleto ‘limit’ or ‘moderate’ their salt intake, Kingsays. The new set-up also made the commit-tee less of a target for pressure from industryand policy-makers.“It shielded us,”she says.

But the literature is far from definitiveabout the best diet.There are few long-term orwell-controlled clinical nutrition trials avail-able, so the committee relied heavily on epi-demiological and observational studies (see

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‘How is science converted to dietary advice?’page 798 and Nature 428, 252–254;2004).

These uncertainties left plenty of room forquibbling about the wording of the guide-lines, say critics of the process,who have beenquick to point out the fingerprints of the foodindustry in the small print. One charge lev-elled at this and previous guidelines is thatthey tell consumers only what foods theyought to eat — such as lean cuts of meat andlow-fat dairy products — without spellingout foods to avoid, such as processed snacks,fast food or red meat dripping with saturatedfat. “They’re saying the right thing but notquite giving it the teeth it needs,” says CarlosCamargo, himself a member of the scientificcommittee and an epidemiologist at the Harvard School of Public Health in Boston.

Cream of the cropA more specific industry influence, criticscontend, is the recommendation to con-sume more dairy products — the equiva-lent of three cups of milk a day, up frombetween two and three cups last time. Theysay that this increase provides most peoplewith unnecessary calories, that it is possibleto achieve recommended intakes of calciumand other nutrients through other means,and that it fails to take into account studieslinking diets high in dairy products with anincreased risk of prostate cancer. Theincrease is “one of the strongest influencesof the food industry” in the report, saysWalter Willett, a nutrition epidemiologist atthe Harvard School of Public Health.

Concerns have also been raised about the

The US government’s guidelines for a healthy dietwere released in January by Tommy Thompson(above), but some say influence from parties, suchas the sugar industry, will compromise the advice.

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recommendation on trans-fats. The scien-tific report said that these should not exceed1% of daily energy intake, but the guidelinessay only that trans-fat intake should be kept“as low as possible”. According to Camargo,this was the most significant departure fromthe committee’s recommendations,allowingthose putting together school meals, forexample, to make only a token effort toreduce the fat. Nutrition researchers criticalof the food industry charge that the languagewas softened under industry pressure toavoid costly revamping of productionprocesses that rely on cheap vegetable oils.

For its part, the food industry says it is justtrying to keep the guidelines fair. Industryrepresentatives, as well as other interestgroups, were invited to provide the commit-tee with written and oral comments duringthe literature-review phase and to makecomments after its report was published.TheNational Dairy Council, for instance, pre-sented evidence supporting its argumentthat dairy foods help people meet their cal-cium and potassium requirements. And theGrocery Manufacturers of America arguedthat added sugars help increase the palatabil-ity of some nutritionally valuable foods.

Reaping benefitsBut industry has other avenues of influenceopen to it. One is through USDA, which, bythe nature of its mission, is more attuned tofarmers’ interests than to public-healthneeds. “It’s the wrong agency to do this, anda blatant conflict of interest,” says MarionNestle, a prominent critic of the food indus-try working at New York University.

A second and more opaque route isthrough lobbying — an integral part of theUS political system — where industry andothers try to influence agency officials by,for example, providing them with relevantdocuments and making personal contacts.

Thompson openly discussed industry’sinfluence at the launch of the guidelines.“The food industry has spent a great deal oftime and money appearing in and observingall of the negotiations and all of the testi-monies that went into compiling the guide-lines,” he said.“They come in and meet withme on a regular basis.”

Although industry may have won keyconcessions, anyone who follows the guide-lines strictly will probably end up in betterhealth. The reason some nutrition expertsare still not happy is that they anticipate littletime or money will be put into spreading orenforcing the advice.

“What is lacking is will on the part of thegovernment and Congress to convert theguidelines into new health and agriculturepolicies and programmes,” says Jacobson.He asserts that doing so would step on major interests such as restaurants, as well as the corn, sugar, processed-food and saltindustries.What is needed, he says, are hard-

hitting, mass-media campaigns to help shiftconsumer demand to healthier products.Some also advocate legislation to subsidizehealthy foods, regulate advertising aimed atchildren, and to require calorie informationto be displayed on restaurant menus.

So far there is little sign that strong imple-mentation is coming.Instead,the US admin-istration has emphasized that diet is a matterof personal choice. “It’s up to the individualto make the right decisions,”said Thompsonin January.

But Ricardo Uauy, an expert on healthand nutrition at the London School ofHygiene and Tropical Medicine, argues thatit is nearly impossible to choose carbo-hydrates or fats “wisely”, as the guidelines

recommend,when manychildren’s cereals con-tain as much as 40%sugar, for instance, andprocessed foods accountfor 80% of the trans-fats that people eat. Nor is iteasy for people to choosefoods with little salt — as

the guidelines advise to lower blood pressure— when 80% of their salt intake comes fromprocessed foods.

Hard to swallowIndeed, the US diet will have to change rad-ically to meet the new advice. At present,many Americans eat a diet that resemblesthe food pyramid turned upside down, withtoo much salt and added sugars and fats,and not enough grains, fruit and vegetables.Without substantial changes in the practicesof the food industry the guidelines will havelittle impact, predicts Uauy.

Others say that the food industry is

already going through a period of evolutionspurred in part by consumer demand. Thepublic discussion of obesity and relatedhealth problems has led to increased aware-ness among consumers and greater scrutinyof the industry by nutrition advocates andthe media. Many fast-food chains haveupdated their image with healthier fare suchas salads and yoghurts. Last year, McDon-ald’s phased out its ‘supersize’ meal options.And PepsiCo has removed trans-fats fromsome of its snacks and has introduced agreater range of bottled waters and fruitjuices as alternatives to sugary drinks.

At the same time, food companies are notabout to abandon their calorie-laden prod-ucts as long as demand for them exists. “Ifpeople want French fries and a doublecheeseburger we’re gonna give them that,”says Bob Goldin, executive vice-president ofTechnomic, a food-industry consulting andresearch firm based in Chicago.

But industry experts say that the shifttowards healthier foods is more than cos-metic. Health and whole foods are one of thebiggest growth areas in an otherwise satu-rated market, and companies are scramblingfor a share of it. They predict that consumerdemand for healthier food will grow, partlyas a result of the dietary guidelines. “It will be a driving factor in the industry going forward, because that is what the consumerwill ultimately want,”Goldin says.

Certainly Americans are hungry for foodadvice, if $2 billion in diet book sales last yearis any indication. But whether it will takemore than a few books and a gentle nudgefrom their federal health department to getthem to eat better and slim down is still up in the air. Declan Butler and Helen Pearson

➧ www.healthierus.gov/dietaryguidelines

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796 NATURE | VOL 433 | 24 FEBRUARY 2005 | www.nature.com/nature

“If people wantFrench fries and a doublecheeseburgerwe’re gonna givethem that.”

— Bob Goldin

Eat yourself fitter: the new US guidelines encourage greater consumption of fruit and vegetables.

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