Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen; German Center for Diabetes Research (DZD e.V.), Tübingen, Germany.
Department of Internal Medicine IV, Division of Endocrinology, Diabetology, and Nephrology, University Hospital Tübingen, Tübingen, Germany.
Int J Obes (Lond). 2020 Feb;44(2):428-437. doi: 10.1038/s41366-019-0400-6. Epub 2019 Jun 18.
Increased portion size is an essential contributor to the current obesity epidemic. The decision of how much to eat before a meal begins (i.e. pre-meal planning), and the attention assigned to this task, plays a vital role in our portion control.
We investigated whether pre-meal planning can be influenced by a shift in mindset in individuals with overweight and obesity in order to influence portion size selection and brain activity.
We investigated the neural underpinnings of pre-meal planning in 36 adults of different weight groups (BMI < 25 kg/m and BMI ≥ 25 kg/m) by means of functional magnetic resonance imaging. To examine the important role of attentional focus, participants were instructed to focus their mindset on the health effects of food, expected pleasure, or their intention to stay full until dinnertime, while choosing their portion size for lunch.
We observed that participants of all weight groups reduced their portion size when adopting a health mindset, which was accompanied by enhanced activation of the self-control network (i.e. left prefrontal cortex). Fullness and pleasure mindsets resulted in contrasting reward responses in individuals with overweight and obesity compared to normal-weight individuals. Under the pleasure mindset, persons with overweight and obesity showed heightened activity in parts of the taste cortex (i.e. right frontal operculum), while the fullness mindset caused reduced activation in the ventral striatum, an important component of the reward system. Moreover, participants with overweight and obesity did not modify their behaviour under the pleasure mindset and selected larger portions than the normal-weight group.
We were able to identify specific brain response patterns as participants made a final choice of a portion size. The results demonstrate that different brain responses and behaviours during pre-meal planning can inform the development of effective strategies for healthy weight management.
食物份量的增加是当前肥胖流行的一个重要因素。用餐前决定吃多少（即餐前计划），以及对这一任务的关注程度，对我们的份量控制起着至关重要的作用。
我们研究了超重和肥胖个体的思维模式转变是否可以影响餐前计划，从而影响份量选择和大脑活动。
我们通过功能性磁共振成像（fMRI）研究了不同体重组（BMI<25kg/m 和 BMI≥25kg/m）的 36 名成年人的餐前计划的神经基础。为了检验注意力焦点的重要作用，参与者被指示将思维集中在食物的健康影响、预期的愉悦感或他们在晚餐前保持饱腹感的意图上，同时选择午餐的份量。
我们观察到，所有体重组的参与者在采用健康思维模式时都会减少他们的份量选择，这伴随着自我控制网络（即左前额叶皮层）的增强激活。与正常体重个体相比，超重和肥胖个体的饱腹感和愉悦感思维模式导致了相反的奖励反应。在愉悦感思维模式下，超重和肥胖个体的味觉皮层（即右额前回）表现出更高的活动，而饱腹感思维模式导致了奖励系统的重要组成部分——腹侧纹状体的激活减少。此外，超重和肥胖个体在愉悦感思维模式下没有改变他们的行为，选择的份量比正常体重组更大。
我们能够识别出参与者最终选择份量时的特定大脑反应模式。研究结果表明，餐前计划期间不同的大脑反应和行为可以为健康体重管理策略的制定提供信息。
