Metabolic changes with intermittent fasting.

BACKGROUND: The prevalence of obesity is rising globally and effective strategies to treat obesity are needed. Intermittent fasting, a dietary intervention for weight management, has received growing interest from the general public, as well as healthcare professionals, as a form of lifestyle intervention. METHODS: We executed a rapid review using PUBMED database to identify systematic reviews that examined the impact of intermittent fasting on metabolic indices, published between 2011 and 2022. RESULTS: Intermittent fasting leads to weight loss of a similar magnitude to continuous energy restriction. Most of the evidence shows that intermittent fasting leads to greater fat loss as measured by fat mass (kg) or body fat percentage compared to an ad libitum diet, but fat loss attained during intermittent fasting is not significantly different to continuous energy restriction, although recent evidence shows intermittent fasting to be superior. There is mixed evidence for the impact of intermittent fasting on insulin resistance, fasting glucose and lipid profile. Some studies focused on populations of Muslim people, which showed that Ramadan fasting may lead to weight loss and improvement of metabolic parameters during fasting, although the effects are reversed when fasting is finished. CONCLUSIONS: Intermittent fasting is more effective than an ad libitum dietary intake, and equally or more effective as continuous energy restriction, for weight management. However, there is inconclusive evidence on whether intermittent fasting has a clinically beneficial effect on glucose and lipid metabolism.

Meat versus meat alternatives: which is better for the environment and health? A nutritional and environmental analysis of animal-based products compared with their plant-based alternatives.

BACKGROUND: Poor diets lead to negative health outcomes, including increased risk of noncommunicable diseases. Food systems, most notably agriculture, contribute to greenhouse gas emissions (GHGE) that lead to climate change. Meat consumption plays a role in both health and environmental burden. Consumption of meat alternatives may reduce these harms. The aim was to compare meat products and their plant-based alternatives on nutritional parameters, GHGE and price to examine if it is feasible and beneficial for policymakers and health professionals to recommend meat alternatives. METHODS: Data on nutritional information and cost for 99 selected products were collected from five UK supermarkets. Estimates for GHGEs for 97 of these products were found through secondary articles. Median values for nutritional value, GHGE (kgCO2 e) and price per 100 g were calculated to allow comparisons between meat products and their alternatives. Mann-Whitney U tests were used to look for significant differences for each nutrient, emissions and price. RESULTS: Meat alternatives contained significantly more fibre and sugar and were significantly higher in price compared to the equivalent meat products. Meat alternatives had a significantly lower number of calories, saturated fat, protein and kgCO2 e than meat products. There was no significant difference in the amount of salt between meat and meat alternatives. CONCLUSIONS: Overall, this paper found that meat alternatives are likely to be better for health according to most parameters, while also being more environmentally friendly, with lower GHGEs. However, the higher price of these products may be a barrier to switching to meat alternatives for the poorest in society.