Study under review: Using the Avocado to Test the Satiety Effects of a Fat-Fiber Combination in Place of Carbohydrate Energy in a Breakfast Meal in Overweight and Obese Men and Women: A Randomized Clinical Trial.
Diets high in refined carbohydrates and saturated fatty acids (SFAs), such as the Western diet, have been associated with coronary heart disease and type 2 diabetes. These diets may cause problems by increasing oxidation and inflammation in the body, as well as elevating glucose and insulin levels. On the other hand, diets high in monounsaturated fatty acids (MUFAs), such as the Mediterranean and DASH diets, have been associated with cardioprotective and beneficial metabolic effects, such as reduced levels of pro-atherogenic LDL (low-density lipoprotein)-cholesterol and improved insulin sensitivity.
A number of previous studies have established a clear link between the macronutrient profile (including dietary fiber) of a given diet and its satiety effects. Although fats are generally considered less satiating than carbohydrate and protein, studies that have used energy equivalent conditions suggest there may not be a difference in satiety from either macronutrient. Reviews have reported inconclusive results regarding the impact of high-fat meals and fiber on satiety, but this may be because of differences in study design and little agreement between hormonal and subjective measures of satiety. Moreover, these studies have been conducted primarily in healthy weight adults, whereas obese or overweight adults may react differently and potentially benefit more from these kinds of dietary changes.
Fats and fibers have been shown to slow gastric emptying, modulate glucose and insulin response, and change gut hormones that influence satiety. Studies suggest that fats stimulate the release of several satiety hormones, including Peptide YY (PYY), cholecystokinin (CCK), and glucagon-like peptide-1 (GLP-1). Delayed absorption of fats from increased fiber intake could lead to greater release of these hormones and enhance satiety, but few studies have focused on the potential combined effect of fat and fiber.
Avocados are high in fat (especially MUFAs) and fiber and have previously demonstrated reductions in desire to eat and increased meal satisfaction when compared to a meal without avocado. This led the authors of the study under review to evaluate the impact of the replacement of carbohydrate with a half (about 68 grams) or a whole (about 136 grams) avocado in energy equivalent meals on glycemic response, endothelial function, satiety, and gut hormones.
Avocados are a good source of fat and fiber, both of which have been shown to slow gastric emptying, modulate glucose and insulin responses, and change gut hormones that influence satiety. The authors of the study under review aimed to evaluate the impact of the replacement of carbohydrate with varying amounts of avocado in energy equivalent meals on glycemic response, endothelial function, satiety, and gut hormones.
Other Articles in Issue #57 (July 2019)
Good meat, bad meat, red meat, white meat
Red meat is linked to poor heart health in observational studies, but recent evidence suggests that this correlation isn't causal. Part of the story may come down to saturated fat content. This trial puts that theory to the test.
Can HMB help maintain muscle in people at risk for muscle loss?
People with serious diseases can lose muscle mass, which impacts their quality of life. This meta-analysis examined whether HMB can help people with illnesses keep some of their muscle mass.
Mini: Mo’ ingredients, mo’ problems
Multi-ingredient pre-workout supplements may be convenient, but they also have their downsides.
Mini: The American Diabetes Association’s consensus report on nutrition therapy for adults with diabetes and prediabetes
We cover some key takeaways from this recent update of the 2014 ADA consensus report.
Pumped up!? Can citrulline really improve athletic performance?
Citrulline is a non-essential amino acid that could boost performance in theory. But does it do so in fact? Here, we review a recent meta-analysis examining this question.
Beyond connective tissue: investigating collagen supplementation for strength and muscle mass
Getting enough protein is an essential part of gaining muscle mass. However, not all protein's created equal. This RCT aimed to explore whether collagen supplementation can help bulk up.
Foods engineered to be cheap and tasty might make you eat more
There is a strong association between eating processed foods and gaining weight. This RCT took great pains to determine whether or not the link is actually causal.