Weight and Avocados (Replace Refined Carbs with Half or Whole Avocado) » BIOME ONBOARD AWARENESS: THE SCIENCE BEHIND FOOD, OUR MICROBIOME, AND DISEASE

Last Updated on May 20, 2019 by Patricia Carter

Summary: Few studies look at the role of nutrient combinations (particularly fat and fiber) to enhance satiety. With avocados the rage now, many wonder about the impact on their waist from eating avocados because they are high in fat. What most don’t realize though is that avocados are inherently rich in fiber and that fiber/fat combo should remind you of another functional food (i.e., nuts) which have loads of documented health benefits! Spoiler alert: If you haven’t begun yet to add avocados to your meal, read on. This newly published study found that those replacing refined carbohydrates with fat and fiber (from avocado), as part of a meal, felt significantly less hungry and more satisfied after 6 hours, compared with those who ate a low-fat, high-carbohydrate meal. Spoiler alert: They also found that this group had a healthy metabolic hormonal response, and that combo can help mitigate overweight and obesity! In other words, isocaloric dietary manipulation with a whole avocado promotes favorable metabolic responses in addition to enhancing satiety and reducing motivation to eat. This study was a randomized three-arm crossover clinical trial, [Zhu et al 2019], and it published in the journal Nutrients. The researchers looked at how meals that SUBSTITUTE a half or whole fresh avocado for refined carbohydrates affects hunger and meal satisfaction both subjectively and physiologically over 6 hours, in overweight and obese adults. Many of us are eating low-fat, high-carbohydrate meals so from a practical standpoint, the population studied represents a typical cohort of middle-aged people at risk for cardio-metabolic disease—a point when realistic dietary changes can make a significant impact on reversing the disease risk trajectory. The cohort, N=31, was relatively healthy overweight or obese volunteers having elevated fasting insulin concentrations with insulin resistance [27]. Listen up –> The important physiological implications learned from the study was that the addition of avocado limited insulin and blood glucose excursions, and this correlated with an intestinal hormone called PYY which is an important messenger associated with the physiological response. What that means is that this study provides more evidence that adding healthy fats and fibers into a regular daily diet can modulate blood sugar and insulin spikes and that can reduce the risk of diabetes and cardiovascular disease. Britt Burton-Freeman, Ph.D., the senior study author and director of the Center for Nutrition Research at Illinois Tech said, “The responses on the different satiety variables was surprising and helps us understand [or] think about how the fat and fiber may work to enhance satiety, even later, in the post-meal period.” End-game thought: E- A -T AVOCADOS in place of the refined carbs!

Weight and Avocados: Replacing refined carbohydrates with fat and fiber (from avocados), positively effected subjective appetite satiety and produced healthy metabolic hormonal response, and that can help mitigate overweight and obesity.

For years, fat has been targeted as one of the main causes of obesity, in part due to behaviors associated with passive over-consumption. In addition, the type of fat mattered (aka refined vegetable oils are not treated by our body the same as fat inherent in whole foods). Moreover, carbohydrates have now come under scrutiny for their role in appetite regulation and weight control, in association with obesity. “There is no ‘one size fits all’ solution when it comes to optimal meal composition for managing appetite,” said Britt Burton-Freeman in a press release. “However, understanding the relationship between food chemistry [what is in the food nutrient AND fiber-wise] and its physiological effects in different populations can reveal opportunities for addressing appetite control and reducing rates of obesity, putting us a step closer to personalized dietary recommendations.”

What’s in an avocado? So much you’ll wonder why you aren’t eating them!

One medium size, fresh Hass avocado (~136 g) is about 72% water and contains ~13.3 g monounsaturated fats, 10 g fiber, and a variety of carotenoids and other bioactive components [25]. Excerpts from [Ware 2017 Medical News Today] reports avocado benefits are:

Vitamins C, E, K, and B-6, as well as riboflavin, niacin, folate, pantothenic acid, magnesium, and potassium.
They also provide lutein, beta-carotene, and zeaxanthin. These are phytochemicals that are especially concentrated in eye tissues providing antioxidant protection to help minimize damage, including from ultraviolet light. Beta-carotene may reduce the risk of developing age-related macular degeneration.
They are the only fruit that contains a substantial amount of healthy omega-3 fatty acids, especially monounsaturated fatty acids (MUFA) (those are also high in EVOO). MUFA support the absorption of fat-soluble vitamins AND fat-soluble antioxidants.
They are high in fiber (half an avocado has about 6-7 grams). Eating foods with natural fiber can help prevent constipation, maintain a healthy digestive tract, and lower the risk of colon cancer. Eating fiber helps with daily excretion of toxins through the bile and stool. Recent studies have shown that dietary fiber may also play a role in regulating the immune system and inflammation. The Department of Internal Medicine and Nutritional Sciences Program of the University of Kentucky, high fiber intakes are associated with significantly lower risks of developing coronary heart disease, stroke, hypertension, diabetes, obesity, and certain gastrointestinal diseases. Increased fiber intake has also been shown to lower blood pressure and cholesterol levels, improve insulin sensitivity, and enhance weight loss for obese individuals.
Contain substances that have antimicrobial activity, particularly against Escherichia coli, a leading cause of food poisoning.
Contains 25 milligrams of a natural plant sterol called beta-sitosterol per ounce of avocado. Regular consumption of beta-sitosterol and other plant sterols has been seen to help maintain healthy cholesterol levels.
Half of an avocado provides ~25 percent of the daily recommended intake of vitamin K which is important for bone health as it increases calcium absorption and reduces urinary excretion of calcium. Vitamin D gets all the press and it is important as well because it that tells calcium where to go in the body (into the bone and not the tissues/arteries). But Vitamin K increases calcium absorption instead of its excretion.
Is high in folate. Folate is often associated with reduced risk of birth defects like neural tube defects and miscarriage, but sufficient folate may also help to decrease the risk of depression because folate helps to prevent the build-up of homocysteine, a substance that can impair circulation and delivery of nutrients to the brain. Excess homocysteine can also interfere with the production of serotonin, dopamine, and norepinephrine, which regulate mood, sleep, and appetite. Sufficient folate may also protect against colon, stomach, pancreatic, and cervical cancers.
The phytochemicals extracted from avocado can selectively inhibit the growth of precancerous and cancerous cells and cause the death of cancer cells, while encouraging the proliferation of immune system cells called lymphocytes. These phytochemicals have also been shown to decrease chromosomal damage caused by cyclophosphamide, a chemotherapy drug.

Mechanisms behind fat & fiber from [Zhu et al 2019]:

Fat is essential for every single cell in the body. Eating healthy fats supports skin health, enhances the absorption of fat-soluble vitamins, minerals, and other nutrients, and may even help boost the immune system.
Avocados are full of healthy, beneficial fats that help to keep you full and satiated. When you consume fat, your brain receives a signal to turn off your appetite. Eating fat slows the breakdown of carbs, which helps to keep sugar levels in the blood stable.
Fats and some fibers slow gastric emptying, delay nutrient absorption, modulate glucose and insulin responses, and alter gut hormones involved in satiety [7,17,18,19].
Fats are potent stimulators of certain satiety peptides, including cholecystokinin (CCK), peptide YY (PYY) and glucagon-like peptide (GLP)-1 [20,21,22,23]. Delaying absorption of fat with fibers could result in increased release of these peptides and enhance satiety, due to similarities in their physiological effects.
[Zhu et al 2019] findings suggest that for overweight or obese individuals, that replacement strategies for carbohydrate with avocado fats and fibers reduced the post meal insulin demand, increased satiety gut hormone concentrations and improved the subjective profile of satiety. Whether the effects are due to improved insulin sensitivity peripherally or centrally to augment satiety signaling cannot be determined in the present research, but provides the basis for follow up mechanistic work in appropriate models.
Insulin is a master hormone in fuel trafficking and metabolism and has varied roles centrally, including food intake regulation. A dietary pattern that is associated with elevated insulin has been identified with increasing risk of hyperglycemia, metabolic syndrome and insulin resistance [39,40,41], particularly in an overweight/obese population. Hyperinsulinemia and insulin resistance in the periphery can produce hypoinsulinemia and/or modified/dampened insulin signaling in the brain [42,43,44].
Previous work suggests that under energy equivalent conditions, increasing the fat content of a meal or incorporating foods inherently containing fiber into a low-fat meal can enhance satiety over an extended post-meal time period, an effect related to the satiation hormone CCK response post-meal [24].

[Heskey et al 2019] discusses avocado and microbiome impact. This information is very preliminary and much more work needs done.

Details of the NIH [Zhu et al 2019] weight and avocado study:

The working hypothesis is that under energy equivalent conditions, replacing carbohydrate with fat-fiber combination from avocados will enhance satiety and the effects will be related to the meal responsive changes in satiety-mediating hormones.
The cohort was N=31, relatively healthy overweight or obese men and women, 25-60 years of age. This cohort represents a typical cohort of middle-aged people at risk for cardio-metabolic disease—a point when realistic dietary changes can make a significant impact on reversing the disease risk trajectory.
The study tested the effects of replacing carbohydrate with avocado in a meal on satiety, which is the feeling of fullness and reduction in appetite that we experience when we eat.
Participants attended a Pre-Study Visit. At this visit they were instructed on how to complete study questionnaires. They were counseled to restrict for 3 days prior to the Test Day Visit, avocado intake and intake of colored plant foods rich in phytonutrients. For 24h prior to the Test Day Visit, they were asked to restrict alcohol, coffee, tea, and caffeinated beverage intake, and to restrict moderate and vigorous physical activity and drink plenty of water to maintain hydration.
The day before the Test Day Visit, they came to the Illinois Institute of Technology, Chicago, Clinical Nutrition Research Center testing facility (CNRC) to pick up their dinner meal and evening snack. They were asked to get at least 7 hours sleep and to come to the CNRC after an overnight fast of 10 h on each Test Day Visit.
For the Test Day Visit, participants were in the clinic for ~7 h to complete all baseline and post challenge meal testing procedures. Subjects were evaluated for compliance with the protocol (diet, exercise, sleep, fasting), have their body weight and blood pressure measured and baseline flow mediated dilation (FMD) recorded before placement of a catheter and baseline blood sample were taken. Baseline subjective satiety were measured by visual analogue scale (VAS) just before consuming one of the 3 breakfast treatment meals. FMD was measured at 2 time points after breakfast and blood samples and VAS questionnaires were collected at multiple time points over the 6 h postprandial period.
Participants ate a breakfast meal consisting of a bagel sandwich, honeydew melon, oatmeal, and a lemonade-flavored drink on three separate occasions. The researchers replaced carbohydrate energy in a meal with a half (~68g) or a whole (~136g) avocado compared to a control meal without avocado. The control meal was low in fat and high in carbohydrate, while the two test meals contained either half or a whole avocado in the bagel sandwich. The overall calorie count was the same for each meal, but the breakfasts with avocado had triple the amount of fat and only two-thirds the amount of carbohydrate as the control meal.
Participants recorded their subjective feelings of fullness, hunger, tiredness, alertness, desire to eat, how much they wanted to eat, and how satisfied they felt after the meal at regular intervals for 6 hours.
They also provided blood samples for analysis. The researchers looked at hormonal (PYY, GLP-1, ghrelin and insulin) satiety and appetite measured differences in response to 3 different meals over 6 hrs. A secondary goal investigated risk factors for cardio-metabolic disease.
Findings: Participants felt more satisfied after meals containing either a whole or half avocado and said they felt less hungry after meals with a whole avocado. Hormones associated with satiety/appetite were measured in blood. Satiety induced by whole avocado was associated mostly with PYY responses. In contrast, satiety induced by low-fat high carb meal was related mostly to insulin responses. PYY and GLP-1 were significantly elevated after whole avocado vs. low-fat high-carb meal (p < 0.05). Insulin was significantly higher after low-fat high carb meal vs. whole avocado (p < 0.0001). Ghrelin was suppressed more by low-fat high carb meal than whole avocado (p< 0.05). Regression analysis indicated PYY was associated with subjective satiety after whole avocado, whereas increased insulin predicted changes in subjective satiety after low-fat high carb meal.
Concerning the half avocado: The participants reported feeling more satisfied compared to the low-fat high carb meal, but other subjective satiety responses were not significantly suppressed/enhanced by half avocado. Whole and half avocado meals had similar total fat content, but the half avocado meal had less avocado-derived fat and fiber compared to the whole avocado meal. The data suggests that having a higher level of fat in the meal is associated with subjects feeling more satisfied, whereas increasing both the avocado-derived fat and fiber combination offers additional satiety-inducing benefits influencing several subjective variables. It is not yet know whether it is the fat or the fiber component driving this effect. Findings from this study suggest that replacing carbohydrate energy with fat energy in combination with a source of inherent (rather than added) fiber, as demonstrated here with avocados, can increase the satiety value of a meal compared to a low-fat high-carbohydrate meal.
Conclusion: Replacing carbohydrates in a high-carbohydrate meal with avocado-derived fat-fiber combination increased feelings of satiety mediated primarily by PYY vs. insulin. These findings may have important implications for addressing appetite management and metabolic concerns.

Background findings for the [Zhu et al 2019] study:

In 2013, [26] reported that adding about half an avocado to a lunch meal suppressed participants desire to eat and increased how satisfied they felt over 5 h compared to a meal without avocado. However, adding avocado also increased the energy content of the meal. In the same study, postprandial insulin concentrations were reduced after replacing some fat and carbohydrate energy (salad dressing and cookie portions) with avocado [26]. The data suggested that strategic manipulation of meals with avocado, a source of fat and fiber, could promote both satiety and metabolic benefits, which is being investigated in the [Zhu et al 2019]. Achieving both benefits without increasing energy would be ideal, particularly for individuals with weight or glucose control concerns.

Concerning bias of this study: The study received funding from Hass Avocado Board (HAB) and Burton-Freeman is part of the organization’s advisory group.

But Burton-Freeman says, “HAB was not involved with our study design or interpretation of results,” and it confirms what other studies are finding for other whole food healthy fat/fiber combinations: “Nuts are another whole food that delivers healthy fat and fibers. Fats and fibers can be paired in formulated products, but avocados and nuts are examples of plant foods that contain both inherently.” – [Hewings-Martin 2019 Medical News Today]

Special concerns for those on blood thinners like coumadin (warfarin) and Vitamin K foods:

If you are taking blood-thinners, such as Coumadin (warfarin) talk with your doctor. You do not want to suddenly begin to eat more or less foods containing vitamin K as it plays a large role in blood clotting. – [Ware 2017 Medical News Today]

What Was Measured in the [Zhu et al 2019] study.

Primary Outcome measure: Change in postprandial blood glucose concentration response for treatments compared to control over 6-hour postprandial period.

Secondary Outcome Measures [time frame: over 6-hour postprandial period]:

Endothelial function using Flow Mediated Dilation (FMD) for treatments compared to control.
Blood insulin and triglycerides concentration response for treatments compared to control.
Subjective satiety responses using visual analog scales (VAS) for treatments compared to control.
Gut hormones related to satiety for treatments compared to control.

Other Outcome Measures [time frame: over 6hr postprandial period]:

Lipoproteins responses for treatments compared to control.
Inflammation responses for treatments compared to control.
Oxidation responses for treatments compared to control.

Conclusion: There are so many health benefits to eating avocados that it’s time you overcame fat phobia, and seriously considered replacing refined carbohydrates with fat and fiber rich avocados!

\O/ Who knew there was so much fiber in avocados?\O/

\O/ Who knew the combo of whole food fiber with fat is so modulating of appetite AND healthy metabolism? \O/

Guac on with this Guacamole Avocado Mash, PALEO, SCD, GAPS recipe that is always in my fridge. I travel with this too because it’s great for dipping vegetables or using as a salad dressing!

Best in health thru awareness,