Cells, tissues and organisms have the ability to rapidly switch substrate oxidation from carbohydrate to fat in response to changes in nutrient intake, and to changes in energy demands, environmental ...cues and internal signals. In healthy, metabolically normal individuals, substrate switching occurs rapidly and completely; in other words, substrate switching is ‘flexible’. A growing body of evidence demonstrates that a blunted substrate switching from low‐ to high‐fat oxidation exists in obese individuals, as well as in pre‐obese and post‐obese, and that this ‘metabolic inflexibility’ may be a genetically determined trait. A decreased fat oxidation can lead to a positive energy balance under conditions of high‐fat feeding, due to depletion of glycogen stores that stimulates appetite and energy intake through glucostatic and glucogenostatic mechanisms, e.g. hepatic sensing of glycogen stores. Several genetic polymorphisms and single‐nucleotide polymorphisms have been identified that are associated with low‐fat oxidation rates and metabolic inflexibility, and genetic identification of susceptible individuals may lead to personalized prevention of weight gain using fat oxidation stimulants (‘fat burners’) in the future.
The Nova classification of ultra-processed foods (UPFs) rests on poorly defined food processes and the presence of food additives from a chemically heterogeneous group, easily leading to ...misclassification. UPFs are claimed to promote overconsumption of energy and obesity due to high palatability, but little evidence supports effects beyond those that can be accounted for by nutrient composition, energy density, and food matrices. Observational studies link dietary intake of UPFs with obesity, but none have demonstrated independent associations after controlling for likely confounders. A highly cited randomized controlled feeding study that compared a UPF diet with an unprocessed diet showed a rapidly weaning effect on energy intake that can be entirely explained by more conventional and quantifiable dietary factors, including energy density, intrinsic fiber, glycemic load, and added sugar. Clearly, many aspects of food processing can affect health outcomes, but conflating them into the notion of ultra-processing is unnecessary, because the main determinants of chronic disease risk are already captured by existing nutrient profiling systems. In conclusion, the Nova classification adds little to existing nutrient profiling systems; characterizes several healthy, nutrient-dense foods as unhealthy; and is counterproductive to solve the major global food production challenges.
Summary
It is increasingly recognized that there is a connection between diet, intestinal microbiota, intestinal barrier function and the low‐grade inflammation that characterizes the progression ...from obesity to metabolic disturbances, making dietary strategies to modulate the intestinal environment relevant. In this context, the ability of some Gram‐positive anaerobic bacteria to produce the short‐chain fatty acid butyrate is interesting. A lower abundance of butyrate‐producing bacteria has been associated with metabolic risk in humans, and recent studies suggest that butyrate might have an anti‐inflammatory potential that can alleviate obesity‐related metabolic complications, possibly due to its ability to enhance the intestinal barrier function.
Here, we review and discuss the potential of butyrate as an anti‐inflammatory mediator in metabolic diseases, and the potential for dietary interventions increasing the intestinal availability of butyrate.
On the basis of the abundance of specific bacterial genera, the human gut microbiota can be divided into two relatively stable groups that might have a role in personalized nutrition. We studied ...these simplified enterotypes as prognostic markers for successful body fat loss on two different diets. A total of 62 participants with increased waist circumference were randomly assigned to receive an ad libitum New Nordic Diet (NND) high in fiber/whole grain or an Average Danish Diet for 26 weeks. Participants were grouped into two discrete enterotypes by their relative abundance of Prevotella spp. divided by Bacteroides spp. (P/B ratio) obtained by quantitative PCR analysis. Modifications of dietary effects of pre-treatment P/B group were examined by linear mixed models. Among individuals with high P/B the NND resulted in a 3.15 kg (95% confidence interval (CI): 1.55; 4.76, P<0.001) larger body fat loss compared with ADD, whereas no differences was observed among individuals with low P/B (0.88 kg (95% CI: -0.61; 2.37, P=0.25)). Consequently, a 2.27 kg (95% CI: 0.09; 4.45, P=0.041) difference in responsiveness to the diets were found between the two groups. In summary, subjects with high P/B ratio appeared more susceptible to lose body fat on diets high in fiber and whole grain than subjects with a low P/B ratio.
The importance of the relative dietary content of protein, carbohydrate and the type of carbohydrate (that is, glycemic index (GI)) for weight control under ad libitum conditions has been ...controversial owing to the lack of large scale studies with high diet adherence. The Diet, Obesity and Genes (DioGenes) European multicentre trial examined the importance of a slight increase in dietary protein content, reduction in carbohydrate and the importance of choosing low (LGI) vs high GI (HGI) carbohydrates for weight control in 932 obese families. Only the adults underwent a diet of 800 kcal per day for 8 weeks, and after losing ~11kg they were randomized to one of five energy ad libitum diets for 6 months. The diets differed in protein content and GI. The high-protein (HP) diet groups consumed 5.4% points more energy from protein than the normal protein (NP) groups, and the LGI diet groups achieved 5.1% lower GI than the HGI groups. The effect of HP and LGI was additive on weight loss and maintenance, and the combination was successful in preventing weight regain and reducing drop-out rate among the adults after the 11kg weight loss. This diet also reduced body fatness and prevalence of overweight and obesity among their children and had consistent beneficial effects on blood pressure, blood lipids and inflammation in both parents and children. After 1 year, mainly the HP effects were maintained. Putative genes have been identified that suggest this diet to be particularly effective in 67% of the population. In conclusion, the DioGenes diet has shown to be effective for prevention of weight regain and for weight reduction in overweight children under ad libitum conditions. The less-restrictive dietary approach fits into a normal food culture, and has been translated into popular diet and cook books in several languages.
Summary
Decades of research have reported only weak associations between the intakes of specific foods or drinks and weight gain and obesity. Randomized controlled dietary intervention trials have ...only shown very modest effects of changes in nutrient intake and diet composition on body weight in obese subjects. This review summarizes the scientific evidence on the role mental stress (either in or not in association with impaired sleep) may play in poor sleep, enhanced appetite, cravings and decreased motivation for physical activity. All these factors contribute to weight gain and obesity, possibly via decreasing the efficacy of weight loss interventions. We also review evidence for the role that lifestyle and stress management may play in achieving weight loss in stress‐vulnerable individuals with overweight.
We wanted to assess the effect of rapid diet-induced weight loss on the function of obese, knee osteoarthritis (OA) patients.
Eighty patients with knee OA, 89% women (
n
=
71), were recruited. Mean ...(SD) body-mass index (BMI) was 35.9 (5.1) kg/m
2 and age 62.6 (11.1) years. Patients were randomized to either a low-energy diet (LED 3.4
MJ/day), or a control diet (5
MJ/day). The LED group had weekly dietary sessions, whereas the control group was given a booklet describing weight loss practices. Changes in body weight and body composition were examined as independent predictors of changes in knee OA symptoms. Symptoms were monitored by the Western Ontario and McMaster Universities' (WOMAC) OA index.
The LED and control group lost a mean (SE) of 11.1 (0.6)% and 4.3 (0.6)%, respectively, with a mean difference being 6.8% (95% confidence interval (CI): 5.5 to 8.1%;
P
<
0.0001). The decrease in body fat percent was higher in the LED group, 2.2% (1.5 to 3.0%;
P
<
0.0001). The total WOMAC index improved in the LED group (
P
<
0.0001), but not in the control group (
P
=
0.12), mean difference: −219.3
mm (−369.2 to −69.4
mm;
P
=
0.005). The ‘Number Needed to Treat (NNT)’ to ensure an improvement in WOMAC
≥
50% was 3.4 (2.1 to 8.8) patients. Changes in total WOMAC index were best predicted by the reduction of body fat percent, with a 9.4% (4.8 to 13.9%) improvement in WOMAC for each percent of body fat reduced (
P
=
0.0005).
In our patients with knee OA, a weight reduction of 10% improved function by 28%. LED might be of advantage to control diet because of the rapidity of weight loss and a more significant loss of body fat.
The aim of this systematic review and meta-analysis was to summarize the evidence from observational studies assessing the association between intake of trans fatty acids (TFA) and the risk of ...coronary heart disease (CHD), with a specific emphasis on distinguishing between TFA of industrial and ruminant origin. By searching five bibliographic databases, analyses from six published and two unpublished prospective cohort studies, assessing the association of intake of TFA with fatal and/or non-fatal CHD, were identified. Four and three studies reported separate associations for intake of ruminant or industrial-TFA, respectively. The pooled relative risk estimates for comparison of extreme quintiles of total-TFA intake (corresponding to intake increments ranging from 2.8 to ∼10 g/day) were 1.22 (95% confidence interval: 1.08-1.38; P=0.002) for CHD events and 1.24 (1.07-1.43; P=0.003) for fatal CHD. Ruminant-TFA intake (increments ranging from 0.5 to 1.9 g/day) was not significantly associated with risk of CHD (risk ratio (RR)=0.92 (0.76-1.11); P=0.36), and neither was industrial-TFA intake, although there was a trend towards a positive association (RR=1.21 (0.97-1.50); P=0.09). In conclusion, our analysis suggests that industrial-TFA may be positively related to CHD, whereas ruminant-TFA is not, but the limited number of available studies prohibits any firm conclusions concerning whether the source of TFA is important. The null association of ruminant-TFA with CHD risk may be due to lower intake levels.
Can gestational weight gain in obese women be restricted by 10-h dietary consultations and does this restriction impact the pregnancy-induced changes in glucose metabolism?
A randomized controlled ...trial with or without restriction of gestational weight gain to 6-7 kg by ten 1-h dietary consultations.
Fifty nondiabetic nonsmoking Caucasian obese pregnant women were randomized into intervention group (n=23, 28+/-4 years, prepregnant body mass index (BMI) 35+/-4 kg m(-2)) or control group (n=27, 30+/-5 years, prepregnant BMI 35+/-3 kg m(-2)).
The weight development was measured at inclusion (15 weeks), at 27 weeks, and 36 weeks of gestation. The dietary intakes were reported in the respective weeks by three 7-day weighed food records and blood samples for analyses of fasting s-insulin, s-leptin, b-glucose, and 2-h b-glucose after an oral glucose tolerance test were collected.
The women in the intervention group successfully limited their energy intake, and restricted the gestational weight gain to 6.6 kg vs a gain of 13.3 kg in the control group (P=0.002, 95% confidence interval (CI): 2.6-10.8 kg). Both s-insulin and s-leptin were reduced by 20% in the intervention group compared to the control group at week 27, mean difference: -16 pmol l(-1) (P=0.04, 95% CI: -32 to -1) for insulin and -23 ng ml(-1) (P=0.004, 95% CI: -39 to -8) for leptin. At 36 weeks of gestation, the s-insulin was further reduced by 23%, -25 pmol l(-1) (-47 to -4, P=0.022) and the fasting b-glucose were reduced by 8% compared with the control group (-0.3 mmol l(-1), -0.6 to -0.0, P=0.03).
Restriction of gestational weight gain in obese women is achievable and reduces the deterioration in the glucose metabolism.
This review aims to assess by meta-analysis of randomised controlled trials (RCTs) changes in pain and function when overweight patients with knee osteoarthritis (OA) achieve a weight loss. ...Systematic searches were performed and reference lists from the retrieved trials were searched. RCTs were enclosed in the systematic review if they explicitly stated diagnosis of knee OA and reported a weight change as the only difference in intervention from the control group. Outcome Measures for Arthritis Clinical Trials III outcome variables were considered for analysis. Effect size (ES) was calculated using RevMan, and meta-regression analyses were performed using weighted estimates from the random effects analyses. Among 35 potential trials identified, four RCTs including five intervention/control groups met our inclusion criteria and provided data from 454 patients. Pooled ES for pain and physical disability were 0.20 (95% CI 0 to 0.39) and 0.23 (0.04 to 0.42) at a weight reduction of 6.1 kg (4.7 to 7.6 kg). Meta-regression analysis showed that disability could be significantly improved when weight was reduced over 5.1%, or at the rate of >0.24% reduction per week. Clinical efficacy on pain reduction was present, although not predictable after weight loss. Meta-regression analysis indicated that physical disability of patients with knee OA and overweight diminished after a moderate weight reduction regime. The analysis supported that a weight loss of >5% should be achieved within a 20-week period—that is, 0.25% per week.
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