Custard: a laboratory food that tells you how you eat

Almost everything research knows about custard comes from using it as a laboratory tool. It is smooth, it is easy to make identical, and scientists can hold the calories and the ingredients fixed while changing one thing: the sweetness, the protein, the size of the spoonful. In one of these trials the custard never met a spoon at all. It was delivered into the mouth through a tube. So these are findings about the act of eating. Dessert is the part that got left out. They are still worth reading, because the plainest of them is about you and not about the food. How you eat it changes how much of it you eat. Twenty-two adults eating to fullness stopped at 382 g when the bites were small and took 476 g when the bites were large, about a quarter more of the same custard. Keeping each mouthful in the mouth longer cut intake by 66 g in the second study. Slowing the pace cut intake by 42 g in one study, and only when the food was also held in the mouth longer, while a second study of the same design found no difference at all between slow and fast eating. In the 20 people whose blood was tested, insulin measured once at the end of that slowest meal ran 81 percent higher. That is a single reading at the table, and the study followed nothing after it, so it says nothing about anyone getting healthier or sicker. The form of the food also changed how the same fat showed up in the blood. In 12 adults eating one test meal, custard raised the blood triglyceride response after the meal by up to 122.7 percent over a pudding and a biscuit built to the same composition.

What a real portion looks like

• Twenty-two adults eating chocolate custard to fullness took in 382 g with small bites against 476 g with large ones, so bite size alone moved intake by roughly a quarter. — 22 healthy subjects across seven conditions, custard delivered through a tube with bite size fixed at about 5 g or about 15 g and oral processing time at 3 or 9 seconds (n = 22) Evidence B source
  382 ± 197 g (small bite, 3 s) versus 476 ± 176 g (large bite, 3 s); bite size p < 0.0001, oral processing time p = 0.008
• How creamy a custard looked and smelled set the size of the first bite before any of it was tasted, and bites shrank as soon as the changes made it seem less creamy. — Adults in a series of laboratory studies sucking custard through an 11 mm straw from a two-compartment cup, with colour, odour and visual texture of the viewed custard varied (n = not stated in the abstract) Evidence C source
  First bite larger when the viewed custard was recognised as creamy and smaller when it was not; bite sizes fell significantly when creaminess was reduced

What your body absorbs

• In 12 adults given four model foods of the same composition in one test meal, custard raised the blood triglyceride response after eating by up to 122.7% over pudding and biscuit, so the same fat appeared in the blood differently depending on the structure of the food. — 12 healthy subjects in a randomised open-label cross-over postprandial trial of custard, pudding, sponge cake and biscuit (n = 12) Evidence B source
  Custard postprandial triglyceride response up to +122.7% versus pudding and biscuit (p < 0.0001), from one test meal
• When a custard was used to carry 20 g of acylated maize starch, 73% to 76% of the attached short-chain fatty acids passed the small intestine undigested in people with an ileostomy, whose gut stands in here for the small intestine of everyone else. — Ileostomy volunteers, standing in as a model of the small intestine, given single doses of custards with acetylated, propionylated or butyrylated high-amylose maize starch and two control starches. The acylated starch is what was tested here, not the custard (n = not stated in the abstract) Evidence B source
  73% to 76% of esterified short-chain fatty acids recovered in stoma effluent; resistance greater for the high-amylose starches than for low-amylose starch (p < 0.001)

What it does to your health

• Keeping chocolate custard in the mouth longer cut intake by 66 g in study 2. Slowing the pace cut intake by 42 g in study 1, and only in the condition where the food was also held in the mouth longer (p = 0.04), while study 2 found no difference between slow and fast eating (p = 0.35). — 40 adults in study 1 and 20 in study 2, mean age 23 to 24, eating chocolate custard with caramel sauce or caramel fudge until fullness in a 2 by 2 randomised trial (n = 60 across two studies) Evidence B source
  Study 1: 42 ± 15 g less with a slow eating rate, only within the high oro-sensory exposure condition (p = 0.04); study 2: no intake difference between slow and fast eating (p = 0.35), and 66 ± 21 g less with high oro-sensory exposure; insulin 81% higher in the high exposure slow rate condition (p = 0.049), one measurement at the end of the meal in the 20 people whose hormones were taken, with no health outcome followed up
• Making vanilla custard unpleasantly sweet left ghrelin higher at 180 and 240 minutes and insulin lower in the first half hour in 11 men, at the same energy content. — 11 healthy men with normal BMI in a randomised cross-over design, vanilla custard with acesulfame-K versus the same custard without it, one week apart (n = 11) Evidence B source
  Ghrelin higher for the low acceptability meal at 180 and 240 minutes (P < .05); insulin higher for the acceptable meal at 15 and 30 minutes (P < .05); appetite scores did not differ between meals
• In 25 adults fed custards built on three different proteins, whey at 10% of energy cut hunger more than casein or soy, and none of the three changed how much was eaten at the next meal. — 25 healthy adults, mean age 22, single-blind randomised design, breakfast custards with casein, soy or whey protein at 10 or 25 percent of energy (n = 25) Evidence B source
  Whey lowered hunger more than casein or soy at 10 percent of energy (p < 0.05); at 25 percent no difference in appetite ratings; no difference in later energy intake
• Thirty healthy adults were split into three groups of ten, and each group ate a different Thai dessert of a different glycaemic index and a different weight, a 192 g custard cake, a 98 g curry puff or a 68 g cracker. After 24 hours Collinsella and Bifidobacterium were lower in the high glycaemic cracker group, and the authors call the shift temporary. — 30 healthy adults aged 18 to 45 in an open-label parallel randomised trial, ten per group, three different Thai desserts of different glycaemic index and different weight (192 g custard cake, 98 g curry puff, 68 g cracker) eaten with a standard breakfast (n = 30, ten per group) Evidence B source
  Collinsella and Bifidobacterium lower in the high glycaemic group; sugar intake negatively correlated with Lactobacillus in the medium and high groups but not the low one

The bottom line

Two smaller findings come from the same set of trials. Protein type moved hunger a little and moved nothing after it. In 25 adults, whey at 10 percent of energy cut hunger more than casein or soy, at 25 percent even that difference disappeared, and none of the three changed how much anyone ate at the next meal. Sweetness that goes wrong has a measurable afterlife. Eleven men ate a vanilla custard made unpleasantly sweet with acesulfame-K, and their ghrelin stayed higher at 180 and 240 minutes while insulin ran lower in the first half hour, at the same energy content. Their appetite ratings did not differ between the two meals, so what the hormones did and what the men felt were not the same story. Two other studies are about products you would not make at home. Thirty adults were split into three groups of ten, and each group ate a different Thai dessert of a different weight, a 192 g custard cake, a 98 g curry puff or a 68 g cracker. After 24 hours two gut bacteria, Collinsella and Bifidobacterium, were lower in the cracker group, and the authors call the shift temporary. What was compared there is three desserts, not a property of custard. A custard carrying 20 g of acylated maize starch delivered 73 to 76 percent of its attached short-chain fatty acids past the small intestine, measured in people with an ileostomy, whose gut is used here as a model of the small intestine of everyone else. That starch is a designed research ingredient, and it is the thing being tested, not the custard around it. Your eyes get the first vote. When the custard looked and smelled creamy, people took a bigger first bite before tasting any of it, and the bites shrank as soon as the creaminess was turned down. That work is a laboratory study without randomisation, and the abstract does not say how many people took part, so read it as a description of how appetite gets cued rather than as an instruction. Now the part we cannot give you. We hold no evidence card on who should be careful with custard, so this page carries no safety section at all. That is a gap in what we have checked, and we would rather say so than let the silence read as reassurance. Custard is eggs, milk and sugar, and the questions those raise, from egg and cow milk allergy to blood sugar to how a chilled egg dessert is stored, sit outside the evidence gathered here. Ask them of a person who knows your situation. We also have no USDA record for custard in this cohort, which is why there is no nutrient table above. Every number on this page comes from the trials listed in the sources and from nowhere else.

Sources

1. cust-r1-03 · randomised controlled trial
   Subjects consumed significantly more when bite sizes were large than when they were small (bite size effect: P < 0.0001) and when OPT was 3 s rather than 9 s (OPT effect: P = 0.008)...Under large bite size conditions, ad libitum intakes were much higher: 476 +/- 176 g (3-s OPT) and 432 +/- 163 g (9-s OPT).
   Am J Clin Nutr, 2009 · checked 2026-09-23
2. cust-r1-08 · clinical trial
   The results from the first study indicated that the recognition of oral qualities of custards via vision or olfaction determined the size of the first bite...Bite sizes decreased significantly when these variations reduced creaminess.
   Physiol Behav, 2004 · checked 2026-09-23
3. cust-r1-01 · randomised controlled trial
   Custard triglyceride response is higher than pudding and biscuit responses (up to +122.7%, p < 0.0001). Sponge cake vitamin D3 response is higher than biscuit response (+26.6%, p = 0.047).
   Mol Nutr Food Res, 2020 · checked 2026-09-23
4. cust-r1-02 · randomised controlled trial
   Volunteers consumed single doses of custards containing 20 g cooked acetylated, propionylated, or butyrylated high-amylose maize starches (HAMSA, HAMSP, and HAMSB, respectively) on each collection day...Between 73% and 76% of the esterified SCFAs survived small intestinal digestion, which showed the potential of acylated starches to deliver specific SCFAs to the large bowel.
   Am J Clin Nutr, 2007 · checked 2026-09-23
5. cust-r1-04 · randomised controlled trial
   In study 1, participants ate (mean ± SEM) 42 ± 15 g less in the slow- than in the fast-ER condition, only within the high-OSE condition (P = 0.04). In study 2, participants ate 66 ± 21 g less in the high- than in the low-OSE condition and there were no intake differences between slow and fast ER (P = 0.35).
   Am J Clin Nutr, 2020 · checked 2026-09-23
6. cust-r1-05 · randomised controlled trial
   Subjects were randomly assigned to 1 of 2 meals: vanilla custard with acesulfame-K (LA, excessively sweet) or without it (HA)...Ghrelin levels were significantly higher (P<.05) for LA meal at 180 and 240 minutes than the HA meal.
   Nutr Res, 2018 · checked 2026-09-23
7. cust-r1-06 · randomised controlled trial
   At 10En%, whey decreased hunger more than casein or soy (p <0.05), coinciding with higher leucine, lysine, tryptophan, isoleucine, and threonine responses (p<0.05)...There were no differences in EI.
   Physiol Behav, 2009 · checked 2026-09-23
8. cust-r1-07 · randomised controlled trial
   Participants were randomly assigned to one of three groups: Phetchaburi's Custard Cake (192 g, low-GI group, n = 10), Saraburi's Curry Puff (98 g, medium-GI group, n = 10), and Lampang's Crispy Rice Cracker (68 g, high-GI group, n = 10), each consumed alongside their standard breakfast...The findings suggest that Thai desserts with varying GI levels can influence specific gut bacteria, though these effects may be temporary.
   Nutrients, 2024 · checked 2026-09-23