NZ Herald
  • Home
  • Latest news
  • Herald NOW
  • Video
  • New Zealand
  • Sport
  • World
  • Business
  • Entertainment
  • Podcasts
  • Quizzes
  • Opinion
  • Lifestyle
  • Travel
  • Viva
  • Weather

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • New Zealand
    • All New Zealand
    • Crime
    • Politics
    • Education
    • Open Justice
    • Scam Update
  • Herald NOW
  • On The Up
  • World
    • All World
    • Australia
    • Asia
    • UK
    • United States
    • Middle East
    • Europe
    • Pacific
  • Business
    • All Business
    • MarketsSharesCurrencyCommoditiesStock TakesCrypto
    • Markets with Madison
    • Media Insider
    • Business analysis
    • Personal financeKiwiSaverInterest ratesTaxInvestment
    • EconomyInflationGDPOfficial cash rateEmployment
    • Small business
    • Business reportsMood of the BoardroomProject AucklandSustainable business and financeCapital markets reportAgribusiness reportInfrastructure reportDynamic business
    • Deloitte Top 200 Awards
    • CompaniesAged CareAgribusinessAirlinesBanking and financeConstructionEnergyFreight and logisticsHealthcareManufacturingMedia and MarketingRetailTelecommunicationsTourism
  • Opinion
    • All Opinion
    • Analysis
    • Editorials
    • Business analysis
    • Premium opinion
    • Letters to the editor
  • Politics
  • Sport
    • All Sport
    • OlympicsParalympics
    • RugbySuper RugbyNPCAll BlacksBlack FernsRugby sevensSchool rugby
    • CricketBlack CapsWhite Ferns
    • Racing
    • NetballSilver Ferns
    • LeagueWarriorsNRL
    • FootballWellington PhoenixAuckland FCAll WhitesFootball FernsEnglish Premier League
    • GolfNZ Open
    • MotorsportFormula 1
    • Boxing
    • UFC
    • BasketballNBABreakersTall BlacksTall Ferns
    • Tennis
    • Cycling
    • Athletics
    • SailingAmerica's CupSailGP
    • Rowing
  • Lifestyle
    • All Lifestyle
    • Viva - Food, fashion & beauty
    • Society Insider
    • Royals
    • Sex & relationships
    • Food & drinkRecipesRecipe collectionsRestaurant reviewsRestaurant bookings
    • Health & wellbeing
    • Fashion & beauty
    • Pets & animals
    • The Selection - Shop the trendsShop fashionShop beautyShop entertainmentShop giftsShop home & living
    • Milford's Investing Place
  • Entertainment
    • All Entertainment
    • TV
    • MoviesMovie reviews
    • MusicMusic reviews
    • BooksBook reviews
    • Culture
    • ReviewsBook reviewsMovie reviewsMusic reviewsRestaurant reviews
  • Travel
    • All Travel
    • News
    • New ZealandNorthlandAucklandWellingtonCanterburyOtago / QueenstownNelson-TasmanBest NZ beaches
    • International travelAustraliaPacific IslandsEuropeUKUSAAfricaAsia
    • Rail holidays
    • Cruise holidays
    • Ski holidays
    • Luxury travel
    • Adventure travel
  • Kāhu Māori news
  • Environment
    • All Environment
    • Our Green Future
  • Talanoa Pacific news
  • Property
    • All Property
    • Property Insider
    • Interest rates tracker
    • Residential property listings
    • Commercial property listings
  • Health
  • Technology
    • All Technology
    • AI
    • Social media
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology
    • Opinion
    • Audio & podcasts
  • Weather forecasts
    • All Weather forecasts
    • Kaitaia
    • Whangārei
    • Dargaville
    • Auckland
    • Thames
    • Tauranga
    • Hamilton
    • Whakatāne
    • Rotorua
    • Tokoroa
    • Te Kuiti
    • Taumaranui
    • Taupō
    • Gisborne
    • New Plymouth
    • Napier
    • Hastings
    • Dannevirke
    • Whanganui
    • Palmerston North
    • Levin
    • Paraparaumu
    • Masterton
    • Wellington
    • Motueka
    • Nelson
    • Blenheim
    • Westport
    • Reefton
    • Kaikōura
    • Greymouth
    • Hokitika
    • Christchurch
    • Ashburton
    • Timaru
    • Wānaka
    • Oamaru
    • Queenstown
    • Dunedin
    • Gore
    • Invercargill
  • Meet the journalists
  • Promotions & competitions
  • OneRoof property listings
  • Driven car news

Puzzles & Quizzes

  • Puzzles
    • All Puzzles
    • Sudoku
    • Code Cracker
    • Crosswords
    • Cryptic crossword
    • Wordsearch
  • Quizzes
    • All Quizzes
    • Morning quiz
    • Afternoon quiz
    • Sports quiz

Regions

  • Northland
    • All Northland
    • Far North
    • Kaitaia
    • Kerikeri
    • Kaikohe
    • Bay of Islands
    • Whangarei
    • Dargaville
    • Kaipara
    • Mangawhai
  • Auckland
  • Waikato
    • All Waikato
    • Hamilton
    • Coromandel & Hauraki
    • Matamata & Piako
    • Cambridge
    • Te Awamutu
    • Tokoroa & South Waikato
    • Taupō & Tūrangi
  • Bay of Plenty
    • All Bay of Plenty
    • Katikati
    • Tauranga
    • Mount Maunganui
    • Pāpāmoa
    • Te Puke
    • Whakatāne
  • Rotorua
  • Hawke's Bay
    • All Hawke's Bay
    • Napier
    • Hastings
    • Havelock North
    • Central Hawke's Bay
    • Wairoa
  • Taranaki
    • All Taranaki
    • Stratford
    • New Plymouth
    • Hāwera
  • Manawatū - Whanganui
    • All Manawatū - Whanganui
    • Whanganui
    • Palmerston North
    • Manawatū
    • Tararua
    • Horowhenua
  • Wellington
    • All Wellington
    • Kapiti
    • Wairarapa
    • Upper Hutt
    • Lower Hutt
  • Nelson & Tasman
    • All Nelson & Tasman
    • Motueka
    • Nelson
    • Tasman
  • Marlborough
  • West Coast
  • Canterbury
    • All Canterbury
    • Kaikōura
    • Christchurch
    • Ashburton
    • Timaru
  • Otago
    • All Otago
    • Oamaru
    • Dunedin
    • Balclutha
    • Alexandra
    • Queenstown
    • Wanaka
  • Southland
    • All Southland
    • Invercargill
    • Gore
    • Stewart Island
  • Gisborne

Media

  • Video
    • All Video
    • NZ news video
    • Herald NOW
    • Business news video
    • Politics news video
    • Sport video
    • World news video
    • Lifestyle video
    • Entertainment video
    • Travel video
    • Markets with Madison
    • Kea Kids news
  • Podcasts
    • All Podcasts
    • The Front Page
    • On the Tiles
    • Ask me Anything
    • The Little Things
  • Cartoons
  • Photo galleries
  • Today's Paper - E-editions
  • Photo sales
  • Classifieds

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / Lifestyle

Could a keto diet be bad for athletes' bones?

By Gretchen Reynolds
New York Times·
12 Feb, 2020 08:58 PM5 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

    Reminder, this is a Premium article and requires a subscription to read.

Race walkers on a low-carbohydrate, high-fat ketogenic diet showed early signs indicative of bone loss. Photo / Christopher Testani, The New York Times

Race walkers on a low-carbohydrate, high-fat ketogenic diet showed early signs indicative of bone loss. Photo / Christopher Testani, The New York Times

A low-carbohydrate, high-fat ketogenic diet could alter bone health in athletes, according to a thought-provoking new study of elite racewalkers and their skeletons. The study, one of the first to track athletes during several weeks of intense training, finds that those following a ketogenic diet developed early signs indicative of bone loss.

The study adds to the considerable existing evidence that how we eat can affect how exercise affects us. It also raises concerns about possible, long-term health effects from popular diet plans, including a high-fat, ketogenic diet.

Anyone interested in health, wellness, weight loss, exercise, food or bestseller lists is familiar, by now, with ketogenic diets. Known more familiarly as keto diets, they are extremely low-carbohydrate, high-fat regimens, with as much as 90 per cent of daily calories coming from fats.

Ketogenic diets, if followed scrupulously, reshape how our bodies fuel themselves. Because carbohydrates can be rapidly metabolised, our bodies typically turn to them first for energy, whether the carbohydrates come from our diets or stored sources in our muscles and livers.

But if people follow a low-carbohydrate, ketogenic diet, they soon burn through their stored carbohydrates and their bodies start relying on fat for energy. The fat must be broken down first, however, and, as part of that process, the liver creates substances known as ketone bodies that can be converted into energy.

Advertisement
Advertise with NZME.

Ketogenic diets are popular now among people hoping to lose weight, control blood sugar or otherwise regulate their health. Some athletes also follow the diet, hoping that it will improve performance, since fat, as fuel, is ample, slow-burning and long-lasting.

Some studies have suggested, though, that low-carbohydrate, high-fat diets might change bone metabolism. Children with epilepsy who use the keto diet to control their condition tend to have low bone density, for instance. And in athletes, going for a day or two without carbohydrates can change some blood markers related to bone health.

But no experiments had tracked bone metabolism in competitive athletes on ketogenic diets for longer periods of time. So, for the new study, which was published in January in Frontiers in Endocrinology, researchers in Australia decided to ask a group of world-class racewalkers if they could fiddle with their food for a few weeks. Thirty of the athletes, all of whom were about to embark on intense training for upcoming world championships and other competitions, agreed. The athletes then sorted themselves into two groups, based on whether they were willing to try a keto diet or not.

Advertisement
Advertise with NZME.

About half said that they were and subsequently began a strict low-carbohydrate, high-fat routine. The other men and women continued with a high-carbohydrate diet. All athletes' meals were matched in terms of how many calories, relative to body weight, they ate.

Before the diets kicked off, though, the researchers drew blood from the athletes before and after a workout, to establish their baseline bone health and other markers of their health and fitness.

Discover more

Lifestyle

How Keto and plant-based diets affect your sex life

20 Aug 07:22 PM
Lifestyle

The keto diet is popular, but is it good for you?

26 Aug 11:00 PM
Lifestyle

What is the keto diet and does it work?

07 Jan 06:00 AM
Lifestyle

Sneaky symbol behind mince 'rip-off'

13 Feb 07:00 AM

Bone is an active tissue, constantly breaking down slightly and remodelling itself in response to the demands we place on it. Knowing this, the researchers checked for the levels of specific substances in the athletes' blood known to be associated with bone breakdown, rebuilding and overall metabolism.

Then the athletes embarked on 3 1/2 weeks of intense training, while eating mostly fat or mostly carbs. Afterward, the researchers again drew their blood and rechecked the markers of bone health.

They found differences. The markers of bone breakdown were higher now among the athletes on the keto diet than at the start of the study, while those indicating bone formation and overall metabolism were lower. These same markers were generally unchanged in the high-carb athletes. The athletes on the ketogenic diet, in other words, showed signs of impaired bone health.

How their bones might have been affected by their eating is still unclear, said Louise Burke, the head of sports nutrition at the Australian Institute of Sport in Canberra and one of the lead authors of the new study.

"We believe that the keto diet may affect bone metabolism due to the downstream effects of low-carbohydrate availability on certain hormones, along with other factors," she said. But more study, of course, is needed.

The researchers also did not look directly at changes, if any, in the athletes' bone density or follow them beyond 3 1/2 weeks. Whether any worrisome effects on bone health would linger, intensify or disappear after a longer period of high-fat eating remains unknown, as does the question of whether those of us who are not world-class racewalkers would be similarly affected, if we work out while eschewing carbs.

Advertisement
Advertise with NZME.

But the study does remind us that the interplay of nutrition and exercise is intricate, and we do not yet fully understand its implications for our health.

Burke and her colleagues plan to study the longer-term effects of ketogenic diets and exercise in future studies.


Written by: Gretchen Reynolds
Photographs by: Christopher Testani
© 2020 THE NEW YORK TIMES

Save

    Share this article

    Reminder, this is a Premium article and requires a subscription to read.

Latest from Lifestyle

Lifestyle

How tinned fish became the star of dining trends

11 Jul 12:00 AM
Premium
Lifestyle

Advice: My brother and I haven’t spoken in four years - can we reconcile?

11 Jul 12:00 AM
Lifestyle

Why this Birkin bag became a $16.6m fashion icon

10 Jul 08:53 PM

Get your kids involved in your reno

sponsored
Advertisement
Advertise with NZME.

Latest from Lifestyle

How tinned fish became the star of dining trends

How tinned fish became the star of dining trends

11 Jul 12:00 AM

From sardine toast to tuna pate, premium tins are leaping from pantry to plate.

Premium
Advice: My brother and I haven’t spoken in four years - can we reconcile?

Advice: My brother and I haven’t spoken in four years - can we reconcile?

11 Jul 12:00 AM
Why this Birkin bag became a $16.6m fashion icon

Why this Birkin bag became a $16.6m fashion icon

10 Jul 08:53 PM
‘Are you having a laugh?’: Boss’ text to former employee goes viral

‘Are you having a laugh?’: Boss’ text to former employee goes viral

10 Jul 08:30 PM
Sponsored: Why heat pumps make winter cheaper
sponsored

Sponsored: Why heat pumps make winter cheaper

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP