The Science of Satiety
I'm often met with a blank stare when I mention the word satiety to clients, friends, or family. Like other medical terms, satiety comes from the Latin word satis which means enough. It’s the root of the word satisfied. We’re often told to eat until we’re satisfied, but for many, this translates to being Thanksgiving Day “full.”
Thanksgiving comes once a year, but with larger restaurant portions and food being omnipresent, we eventually have to say, “enough is enough”. Let’s take a look at what impacts satiety.
What Impacts Satiety?
We know that when food travels through the digestive tract, our stomachs fill and empty, and the process repeats itself at the next meal or snack. Gastric emptying varies in individuals, and some people move slower or faster. A full stomach tells your brain, “I’m full.” Hormones released in the gut impact appetite.
Hormones
Leptin is a hormone made by fat cells that act in your brain to regulate appetite and fat storage. When we feel full after a meal, leptin levels are full, and we typically stop eating. If you’re resistant to leptin, your brain doesn’t respond to leptin, and you don’t feel satisfied after meals and continue to eat. (1)
When you lose weight, leptin levels decrease, which can cause you to feel hungry. Researchers are investigating whether medications can improve leptin resistance to aid in weight management.
One small study found that obese subjects receiving leptin replacement utilized fat stores for energy and were in negative energy balance. More research is needed in this area. (2)
Ghrelin is a peptide hormone made in the stomach lining that also impacts appetite. When ghrelin levels are high, you’ll feel hungry. When levels are low, food is less appealing. Ghrelin works in opposition to leptin though both may contribute to weight control.
Poor sleep or alterations in your circadian rhythm may impact ghrelin and appetite. Shift work (working nights/evenings) is a risk factor for obesity and has been found to increase ghrelin levels, which affects appetite. (3)
Protein and Satiety
The amount of protein you consume may also affect satiety. In a study of 105 adults, subjects were given a standard protein diet (.8 gm/kg) or a high protein (1.34 gm/kg) diet to follow for six months. Although both groups reduced their waist circumference, dietary adherence was better in the high-protein group, leading to higher overall weight loss. (4)
Some research suggests dairy protein (whey) and plant protein (from beans and legumes) may be better for weight loss than animal protein. Scientists think branched-chain amino acids, including methionine, tryptophan, and the metabolite glutamate, may promote satiety. (5)
Fiber
Fiber from plant-based foods may also impact satiety. A small study in men and women with metabolic syndrome found that fiber in black beans reduced hunger and improved satiety compared to fiber supplements or diets without added fiber. (6)
A recent study evaluating the perception of hunger found that participants felt fuller with the addition of a fiber supplement compared to using a placebo. (7)
Dietary fiber intake from beta-glucan (6 grams per day found in oats, beans, and barley) also reduced hunger and food intake in a small group of overweight women. (8)
How Your Clients Can Improve Satiety:
Include high-protein, plant-based foods at meals, such as beans, lentils, quinoa, tofu, tempeh, or edamame.
Have dairy in meals and snacks, such as skim or 1% milk, low-fat cottage cheese, Greek yogurt, kefir, and low-fat cheese.
Add foods with soluble fiber to your meals, like rolled oats, barley, beans, and fresh fruit.
Reduce ultra-processed foods that don’t fill you up. Refined chips, cookies, crackers, pastries, ice cream, and other snacks, to name a few.
Eat calories, don’t drink them. Reduce sweetened beverages, sports drinks, and alcohol.
Have most of your calories earlier in the day. Eating bigger meals earlier in the day may reduce appetite and overall food consumption over the course of the day. (9)
Lisa Andrews, MEd, RD, LD
References:
1. Leptin: What It Is, Function & Levels (clevelandclinic.org)
2. Lawler K, Huang-Doran I, Sonoyama T, Collet TH, Keogh JM, Henning E, O'Rahilly S, Bottolo L, Farooqi IS. Leptin-Mediated Changes in the Human Metabolome. J Clin Endocrinol Metab. 2020 Aug 1;105(8):2541–52. doi: 10.1210/clinem/dgaa251. PMID: 32392278; PMCID: PMC7282709.
3. Qian J, Morris CJ, Caputo R, Garaulet M, Scheer FAJL. Ghrelin is impacted by the endogenous circadian system and by circadian misalignment in humans. Int J Obes (Lond). 2019 Aug;43(8):1644-1649. doi: 10.1038/s41366-018-0208-9. Epub 2018 Sep 19. PMID: 30232416; PMCID: PMC6424662.
4. Pannen ST, Maldonado SG, Nonnenmacher T, Sowah SA, Gruner LF, Watzinger C, Nischwitz K, Ulrich CM, Kaaks R, Schübel R, Grafetstätter M, Kühn T. Adherence and Dietary Composition during Intermittent vs. Continuous Calorie Restriction: Follow-Up Data from a Randomized Controlled Trial in Adults with Overweight or Obesity. Nutrients. 2021 Apr 5;13(4):1195. doi: 10.3390/nu13041195. PMID: 33916366; PMCID: PMC8067073.
5. Simonson M, Boirie Y, Guillet C. Protein, amino acids and obesity treatment. Rev Endocr Metab Disord. 2020 Sep;21(3):341-353. doi: 10.1007/s11154-020-09574-5. PMID: 32827096; PMCID: PMC7455583.
6. Reverri EJ, Randolph JM, Kappagoda CT, Park E, Edirisinghe I, Burton-Freeman BM. Assessing beans as a source of intrinsic fiber on satiety in men and women with metabolic syndrome. Appetite. 2017 Nov 1;118:75-81. doi: 10.1016/j.appet.2017.07.013. Epub 2017 Jul 20. PMID: 28735851.
7. Borkoles E, Krastins D, van der Pols JC, Sims P, Polman R. Short-Term Effect of Additional Daily Dietary Fibre Intake on Appetite, Satiety, Gastrointestinal Comfort, Acceptability, and Feasibility. Nutrients. 2022 Oct 10;14(19):4214. doi: 10.3390/nu14194214. PMID: 36235865; PMCID: PMC9572413.
8. Alptekin İM, Çakiroğlu FP, Örmeci N. Effects of β-glucan and inulin consumption on postprandial appetite, energy intake and food consumption in healthy females: A randomized controlled trial. Nutr Health. 2022 Sep;28(3):433-442. doi: 10.1177/02601060211023256. Epub 2021 Jun 15. PMID: 34128426.
9. Vujović N, Piron MJ, Qian J, Chellappa SL, Nedeltcheva A, Barr D, Heng SW, Kerlin K, Srivastav S, Wang W, Shoji B, Garaulet M, Brady MJ, Scheer FAJL. Late isocaloric eating increases hunger, decreases energy expenditure, and modifies metabolic pathways in adults with overweight and obesity. Cell Metab. 2022 Oct 4;34(10):1486-1498.e7. doi: 10.1016/j.cmet.2022.09.007. PMID: 36198293.