No evidence eating fruits and vegetables promotes weight-loss

fruit veggies 2To lose weight, people often are advised to consume more fruits and vegetables to create the sense of being full, but that may be a dietary dead-end, UAB researchers say in the American Journal of Clinical Nutrition.

Kathryn Kaiser, Ph.D., instructor in the UAB School of Public Health, and a team of investigators at UAB and Purdue University conducted a systematic review and meta-analysis of data for more than 1,200 participants in seven randomized, controlled trials that focused on increasing fruit and vegetable intake to measure any effects on weight-loss. The results show that increased fruit and vegetable consumption per se does not reduce or increase body weight.

“Across the board, all studies we reviewed showed a near-zero effect on weight-loss,” Kaiser said. “Just adding them on top of whatever foods a person may be eating is not likely to cause weight change.

“People make the assumption that higher-fiber foods like fruits and vegetables will displace the less healthy foods and that’s a mechanism to lose weight; but our findings from the best available evidence show that effect doesn’t seem to be present among people simply instructed to increase fruit and vegetable intake. To reduce weight you have to reduce caloric intake.”

“People make the assumption that higher-fiber foods like fruits and vegetables will displace the less healthy foods and that’s a mechanism to lose weight; but our findings from the best available evidence show that effect doesn’t seem to be present among people simply instructed to increase fruit and vegetable intake,” Kaiser said. “To reduce weight you have to reduce caloric intake.”

Kaiser believes a change in public health messaging and study design is needed.

People are spending a great deal of money figuring out how to increase fruit and vegetable intake — which has many benefits to health — but weight-loss isn’t one of them, Kaiser said. “I think working on more multimodal healthy lifestyle interventions would be a better use of time and money.”

Kaiser says more high-quality research is needed to investigate ways in which multiple foods may interact to create healthful weight-loss that can be maintained.

“We need to design mechanistic studies to understand these things better so we can help the public be best informed and know what to do for weight-loss,” she said. “Overly simplified messages don’t seem to be very effective.”

Kaiser’s colleagues at UAB including Andrew W. Brown, Ph.D., Michelle M. Bohan Brown, Ph.D., James M. Shikany, DrPH, and David B. Allison, Ph.D., associate dean for science in the UAB School of Public Health.

Research & Scholarship

  • Graduate training to improve special education services gets a boost
    A $1.25 million grant from the U.S. Department of Education will fund scholarships, provide research opportunities and support collaboration between UAB's schools of Education and Health Professions to improve education services for young children with disabilities. Professor Jennifer Kilgo, Ed.D., who directs Project TransTeam, expects to train 70 scholars in five years.
    posted 6 days ago 106 views
  • Men and women process chronic pain differently
    Robert Sorge, Ph.D., assistant professor of psychology, is lead author of a paper published in Nature Neuroscience online that disputes the assumption that a common pain circuit exists in both sexes. New research shows males and females may use very different biological systems to process pain; the key difference appears to be in the immune system and under control of testosterone.
    posted 29 days ago 348 views
  • Will your self-driving car be programmed to kill you?
    The computer brains inside autonomous vehicles will be fast enough to make life-or-death decisions. But should they? A member of UAB’s national championship-winning Bioethics Bowl team — and the team’s coach, a renowned bioethicist — weigh in on a thorny problem of the dawning robot age.
    posted a while back 558 views
  • “Extra costs of extra weight for older adults”


    UAB research, clinical services featured in PBS story that examines the high and rising costs of health care for obese adults as they age.
    posted a while back 916 views
  • Smartphones are learning new tricks
    sensomatic main imageYou may think your phone can already do everything, but UAB cybersecurity researchers are adapting accelerometers, GPS chips, gyroscopes and other sensors to make phones that can read your mood, eliminate passwords, protect your bank account and more.
    posted a while back 834 views
  • Renowned expert named inaugural director of UAB Informatics Institute
    James J. Cimino, M.D., will lead UAB's new Informatics Institute, which was established in June 2014. Cimino, who previously was the chief of the Laboratory for Informatics Development at the NIH Clinical Center and a senior scientist at the National Library of Medicine, is a national leader in the field of biomedical informatics and co-editor of the most influential textbook on the subject.
    posted a while back 1038 views
  • Research enters data-driven era
    During the past few years, technological innovations have opened up an entirely new way to approach scientific questions. Data-driven research starts with massive information sets — the genomic profiles of thousands of patients, for example, or millions of spam emails — and then searches for emerging patterns in that data. In the latest issue of the U.S. Chamber of Commerce’s "Business Horizon Quarterly", UAB President Ray Watts, M.D., explains the way data-driven research at UAB is being applied to find novel treatments for disease, create new products and businesses and train the next generation of innovation-savvy students.
    posted a while back 1176 views
  • Fulbright scholar here to improve health care in Ukraine

    Iryna Mazhak, Ph.D., a Fulbright Visiting Scholar from Ukraine, is developing a medical sociology course and textbook materials during her nine months at UAB. No such course or textbook exists in her homeland, she says. 

    posted a while back 2937 views
  • How safe are you on the Internet?
    Participate in a brief, large-scale survey of Internet users that will help UAB researchers design strong authentication systems for securing information privacy.
    posted a while back 2500 views