What is the Maximum Amount of Carbohydrates That is Still Able to Induce Ketosis and Suppress Appetite?
Condition: Obesity
MeSH terms: Ketosis
Study type: Interventional

Summary: 
      Two dietary approaches, very low energy diets (VLEDs) and ketogenic low carbohydrate diets
      (KLCDs), have the ability to suppress appetite. The suppression of appetite typically
      observed during these diets is believed (but not clinically proven) to be due to ketosis, a
      condition where circulating concentrations of ketone bodies are increased due to a higher
      production of ketones in the liver. Little is known about the potential mechanisms through
      which ketosis may lead to appetite suppression in VLEDs and KLCDs. A 'ketogenic diet'
      typically contains less than 50 grams carbohydrate per day, yet ketosis has been seen in
      subjects who consume diets with a carbohydrates ranging between 59-192 grams per day.
      Although an association between ketosis and appetite suppression has been established, the
      minimum level of ketosis and maximum carbohydrate intake that is still associated with
      appetite suppression remains unknown and should be explored. The ability to increase
      carbohydrate intake while maintaining a suppressed appetite will allow dieters to consume
      more carbohydrate-rich food that is beneficial for health without feeling more hungry.

      The study, 'can Appetite Suppression be achieved using KEtogenic Diets with more
      carbohydrates?' (ASKED) aimed to:

        -  to identify the maximum carbohydrate intake that is still associated with appetite
           suppression in a low energy diet and to determine the impact of a higher carbohydrate
           intake on appetite suppression, ketosis, body composition, and resting metabolic rate. A

        -  to evaluate the impact of weight loss while in and out of ketosis on markers of appetite
           (appetite related hormones and appetite sensations measured using visual analogue
           scales).
    

Detailed description: 
      A total of 101 healthy, weight stable (< 2 kg variation in BW within the last 3 months),
      adult (18-65 years old) individuals with obesity (body mass index [BMI] 30-45 kg/m2) who were
      not actively trying to lose weight were recruited through advertisements in Facebook, Twitter
      and the intranet of St. Olavs Hospital and the Norwegian University of Science and Technology
      (NTNU) in Trondheim, Norway from May 2017 - August 2018.

      Informed consent was obtained from all participants before enrollment in the study, and
      participants were allowed to withdraw at any time.

      Study participants were randomized to one of three intervention arms: low, medium, or high
      CHO groups. Computer-generated randomization was performed using a block sampling (fixed
      block size) and stratification approach to account for the potential confounding factors of
      sex and BMI (< 35 and ≥ 35 kg/m2). (34, 35). Study participants were not made aware of which
      intervention arm they were allocated to until the end of the trial. All participants
      underwent an 8-week, supervised LED containing different amounts of CHO, followed by 4 weeks
      of gradual refeeding and weight stabilization. Measurements were taken before diet initiation
      (baseline), at the end of the WL phase (week 8) and at the end of the weight stabilization
      phase (week 12) to allow for the evaluation of the impact of WL in or out of ketosis on
      appetite markers.
    

Intervention name(s): Low energy diet 70 gram carbohydrates; Low energy diet 100 gram carbohydrates; Low energy diet 130 gram carbohydrates
Intervention type(s): Other; Other; Other
Intervention description(s): isocaloric 4128 kilojoules/day (1000 kilocalories/day) for men and women, low energy diet containing 70 gram carbohydrates; isocaloric 4128 kilojoules/day (1000 kilocalories/day) for men and women; isocaloric 4128 kilojoules/day (1000 kilocalories/day) for men and women, low energy diet containing 130 gram carbohydrates
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Diet, Reducing; Hunger; Appetite Regulation; Ketogenic Diet; Caloric Restriction; Weight Loss; Ketosis