Evidence that carbohydrate-to-fat ratio and taste, but not energy density or NOVA level of processing, are determinants of food liking and food reward

A Whole Plant-Foods Diet in the Prevention and Treatment of Overweight and Obesity: From Empirical Evidence to Potential Mechanisms

Excess body adiposity, referred to as overweight and obesity, represents a major health concern given that it increases the risk of various diseases, including cardiovascular diseases, type 2 diabetes, and cancer. Body weight reduction can be achieved via a wide variety of dietary strategies as long as an energy deficit is achieved. However, the effect of such diets on disease risk and mortality will depend on the foods included. Increasing evidence shows that consumption of whole plant foods (e.g., fruits, vegetables, whole grains, nuts, seeds, legumes) in place of animal foods (e.g., meat, poultry, dairy, fish, eggs, and seafood and their derivatives) and non-whole plant foods (e.g., refined grains, French fries, sugar-sweetened beverages) is associated with improvements in cardiometabolic risk factors and lower risk of chronic diseases and mortality. This review focuses on the effect of a whole plant-foods diet on overweight and obesity from observational to clinical studies and discusses the potential mechanisms involved. According to existing evidence, a whole plant foods diet seems to be more advantageous than other dietary approaches for the prevention and treatment of excess adiposity given that it is composed of the foods that lead to the best health outcomes.

Reasons Behind (Un)Healthy Eating Among School-Age Children in Southern Peru

In recent decades, rates of childhood overweight and obesity have increased worldwide, surpassing those of adults. Understanding the factors influencing children's food choices is essential to promote healthy eating habits. This study examined why school-aged children make healthy and unhealthy food choices and how parents' eating habits influence their children's choices. Children's ability to rank 25 food pictures according to their healthfulness was assessed using a free sorting task (FST), while parents made a free list of healthy and unhealthy foods, and the cognitive salience index (CSI) was calculated. Children were grouped into two groups based on their responses: one mainly from Moquegua and the other from Puno. In general, children from Moquegua demonstrated a greater ability to identify healthy foods than those from Puno. The CSI provided information on healthy and unhealthy foods in each region. These findings underline the potential of selecting palatable and healthy foods to improve children's diets in the short term and contribute to the development of healthier products in the food industry. In addition, studies in other regions of Peru are recommended to understand children's perceptions better.

Increased BMI is associated with an altered decision-making process during healthy food choices in males and females

Unhealthy diets (rich in calories, sugar, fat, and sodium) are a major cause of obesity. Why individuals struggle to make healthy food choices remains unclear. This study examined how body mass index, biological sex, and eating context influence food attribute perception, the food choice process, and the percentage of healthy food choices. In an online study, males and females with and without obesity (n = 910) rated food images for healthiness and tastiness and made food choices after prompts directing them to choose foods they considered healthy (healthy prompt) or to choose as they would in their daily lives (typical prompt), which aimed to model healthy and typical eating contexts. When foods were classified as healthy or unhealthy using nutritional labeling information, all participants rated healthy foods with larger healthiness ratings, but females rated healthy foods as healthier and tastier than males. Still, participants with obesity had fewer healthy choices (i.e., choosing the food with the largest healthiness rating) regardless of sex and prompt. Further, tastiness differences were more relevant than healthiness differences during healthy food choices among participants with obesity, and more so after the typical prompt. On the contrary, healthiness differences were more relevant among participants with healthy weight regardless of prompt type. Our findings highlight the importance of eating contexts in how individuals use their perception of food attributes during healthy food choices and suggest that increasing the presence of healthy prompts and perceived tastiness of healthy foods may promote healthy food choices among individuals with obesity.

Nutrient clustering, NOVA classification, and nutrient profiling: How do they overlap, and what do they predict about food palatability?

We compared the performance of three food categorisation metrics in predicting palatability (taste pleasantness) using a dataset of 52 foods, each rated virtually (online) by 72-224 participants familiar with the foods in question, as described in Appetite 193 (2024) 107124. The metrics were nutrient clustering, NOVA, and nutrient profiling. The first two of these metrics were developed to identify, respectively: 'hyper-palatable' foods (HPFs); and ultra-processed foods (UPFs), which are claimed to be 'made to be hyper-palatable'. The third metric categorises foods as high fat, sugar, salt (HFSS) foods versus non-HFSS foods. There were overlaps, but also significant differences, in categorisation of the foods by the three metrics: of the 52 foods, 35 (67%) were categorised as HPF, and/or UPF, and/or HFSS, and 17 (33%) were categorised as none of these. There was no significant difference in measured palatability between HPFs and non-HPFs, nor between UPFs and non-UPFs (p ≥ 0.412). HFSS foods were significantly more palatable than non-HFSS foods (p = 0.049). None of the metrics significantly predicted food reward (desire to eat). These results do not support the use of hypothetical combinations of food ingredients as proxies for palatability, as done explicitly by the nutrient clustering and NOVA metrics. To discover what aspects of food composition predict palatability requires measuring the palatability of a wide range of foods that differ in composition, as we do here.

Ketogenic diet but not free-sugar restriction alters glucose tolerance, lipid metabolism, peripheral tissue phenotype, and gut microbiome: RCT

Restricted sugar and ketogenic diets can alter energy balance/metabolism, but decreased energy intake may be compensated by reduced expenditure. In healthy adults, randomization to restricting free sugars or overall carbohydrates (ketogenic diet) for 12 weeks reduces fat mass without changing energy expenditure versus control. Free-sugar restriction minimally affects metabolism or gut microbiome but decreases low-density lipoprotein cholesterol (LDL-C). In contrast, a ketogenic diet decreases glucose tolerance, increases skeletal muscle PDK4, and reduces AMPK and GLUT4 levels. By week 4, the ketogenic diet reduces fasting glucose and increases apolipoprotein B, C-reactive protein, and postprandial glycerol concentrations. However, despite sustained ketosis, these effects are no longer apparent by week 12, when gut microbial beta diversity is altered, possibly reflective of longer-term adjustments to the ketogenic diet and/or energy balance. These data demonstrate that restricting free sugars or overall carbohydrates reduces energy intake without altering physical activity, but with divergent effects on glucose tolerance, lipoprotein profiles, and gut microbiome.

Creation and validation of a NOVA scored picture set to evaluate ultra-processed foods

There has been a rapid shift in the modern food environment towards increased processing in foods consumed in the United States (US) and globally. The NOVA system (not an acronym) for classifying food on degree of processing currently has the most empirical support. Consumption of foods in the NOVA 4 category, ultra-processed foods (UPF), is a risk factor for a host of poor health outcomes including heart disease, stroke, and cancer. Despite these poor health outcomes, UPF make up 58% of calories consumed in the US. Methodologies for assessing the reinforcing and rewarding properties of these foods are necessary tools. The Becker-DeGroot-Marschak auction paradigm (BDM) is a well validated tool for measuring value and is amenable to neuromonitoring environments. To allow for the testing of hypotheses based on level of food processing, we present a picture set of 14 UPF and 14 minimally-processed foods (MPF) matched on visual properties, food characteristics (fat, carbohydrate, cost, etc.), and rated perceptual properties. Further, we report our scoring of these foods using the NOVA classification system and provide additional data from credentialed nutrition professionals and on inter-rater reliability using NOVA, a critique of the system. Finally, we provide all pictures, data, and code used to create this picture set as a tool for researchers.

The hedonic overdrive model best explains high-fat diet-induced obesity in C57BL/6 mice

OBJECTIVE

High-fat diets cause obesity in male mice; however, the underlying mechanisms remain controversial. Here, three contrasting ideas were assessed: hedonic overdrive, reverse causality, and passive overconsumption models.

METHODS

A total of 12 groups of 20 individually housed 12-week-old C57BL/6 male mice were exposed to 12 high-fat diets with varying fat content from 40% to 80% (by calories), protein content from 5% to 30%, and carbohydrate content from 8.4% to 40%. Body weight and food intake were monitored for 30 days after 7 days at baseline on a standard low-fat diet.

RESULTS

After exposure to the diets, energy intake increased first, and body weight followed later. Intake then declined. The peak energy intake was dependent on both dietary protein and carbohydrate, but not the dietary fat and energy density, whereas the rate of decrease in intake was only related to dietary protein. On high-fat diets, the weight of food intake declined, but despite this average reduction of 14.4 g in food intake, they consumed, on average, 357 kJ more energy than at baseline.

CONCLUSIONS

The hedonic overdrive model fit the data best. The other two models were not supported.

Ultra-processed Food and Obesity: What Is the Evidence?

PURPOSE OF REVIEW

Obesity is a growing global healthcare concern. A proposed driver is the recent increase in ultra-processed food (UPF) intake. However, disagreement surrounds the concept of UPF, the strength of evidence, and suggested mechanisms. Therefore, this review aimed to critically appraise the evidence on UPF and obesity.

RECENT FINDINGS

Observational studies demonstrate positive associations between UPF intake, weight gain, and overweight/obesity, more clearly in adults than children/adolescents. This is supported by high-quality clinical data. Several mechanisms are proposed, but current understanding is inconclusive. Greater UPF consumption has been a key driver of obesity. There is a need to change the obesogenic environment to support individuals to reduce their UPF intake. The UPF concept is a novel approach that is not explained with existing nutrient- and food-based frameworks. Critical analysis of methodologies provides confidence, but future observational and experimental research outputs with greater methodological rigor will strengthen findings, which are outlined.