|When it comes to carvings, women are more susceptible to the sugar coating of a doughnut vs. steak in a salt crust.|
You're asking yourselves what this anecdote could possibly have to do with the latest nutrition research from Japan? Well, it confirms the main findings Zhou et al. present in their latest paper in the peer-reviewed journal Public Health Nutrition (Zhou. 2014): Men have a significantly stronger desires for salty and fatty foods, whereas women prefer sweet food after meals.
Before we get into further details (e.g. the fact that the sweetness desire in women was stimulated by increasing fat content of the meal), let's briefly take a look at the study design, first -- The subjects were 130 residents of the Tukushima area who were assigned to two age- and BMI-matched groups according to their sex.
A randomized crossover design was used to investigate each test meal at lunchtime with a 1-week interval between testing sessions. Participants were asked to refrain from skipping meals, to refrain from drinking excessive alcohol and to maintain exercise at a consistent level before each scheduled session. During the study period, participants were randomly assigned into four groups for meals distribution. Group A and group B were administered meals following the sequence of lower to higher ED, and group C and group D were administered meals in the opposite manner. A packed test lunch was systematically provided on aspecified day for six consecutive weeks (Table 1)."The study was designed such that the majority of daily food and energy consumed was from the test foods, according to the 2010 Dietary Reference Intakes for Japanese.
The male vs. female difference and the female sweet tooth are not completely new: Previous studies have already suggested that men are easy to satisfy with salty foods (Rolls. 1981 & 83). Havel et al. on the other hand were able to show that high fat meals reduce the 24h leptin concentration in women (Havel. 1999) and will - at a molecular level - increase the risk for sweet cravings (Ninomiya. 2001) - an energy dense high(er) carbohydrate meal has after all been shown to bring leptin levels back up (Romon. 1990). No wonder Drewnoski et al. found that obese US women tended to list predominantly sweet foods, such as doughnuts, cookies and cake, while obese men list mainly protein/fat sources (meat dishes) among their favorite foods (Drewnowski. 1992)Six types of packed lunches were used as test meals with their basic composition and appearance remaining constant (see Table 2). As you would expect from any "truly" Asian diet, rice was the staple food, and the main dishes were sautéed beef, steamed shiitake mushrooms with mincedfish and mixed Japanese hotchpotch consisting of sweet potato, carrot, radish, dried shiitake mushrooms, bamboo shoot, lotus root and konjac.
|Table 1: Randomized crossover study design of six different types of test meals* in six experimental sessions (Zhou. 2014)|
- control meal (Control), energy 500 kcal and ED 0·8 kcal/g;
- high-meat/low-rice meal (Hmeat), energy 513 kcal and ED 0·7 kcal/g;
- low-vegetable meal (Lveg), energy 427 kcal and ED 1·0 kcal/g;
- medium-fat/low-vegetable meal (MfatLveg), energy 520 kcal and ED 1·2 kcal/g);
- high-fat meal (Hfat), energy 896 kcal and ED 1·3 kcal/g; and
- high-fat/low-vegetable meal (HfatLveg), energy 824 kcal and ED 71·8kcal/g
|Table 2: Energy and macronutrient composition of the test meals (Zhou. 2014)|
Alright, let's finally get to the results - Women like sweets and low rice (carbohydrate) and high fat intake make them irresistible, no matter how much veggies they eat
The main study outcomes were the appetite for fullness, satisfaction and prospective demand, and palatability desire for savoury, sweet, salty and fatty foods ratings, the subjects rated after the individual test meals on a 100 mm visual analogue scale (VAS).
"For example, fullness and satisfaction were rated on the 100-mm lines preceded by the questions: ‘How full do you feel right now?’ and ‘How much satisfaction do you feel right now?’, and anchored on the left by ‘not at all’ andontherightby ‘very much’, respectively." (Zhou. 2014)All participants had been familiarized with the procedure before the first tests were run. We can thus expect that they were able to accurately report their desire for sweet, salty and fatty after consuming the test meals.
|Figure 1: Sweet, salty and fatty desire after test meals in men (top) and women (bottom; Zhou. 2014)|
Women are hedonic eaters and into both fat (for flavor) and sweet
Compared to the men, the women were also much more susceptible to the palatability increase due to increased fat content (compare the graphs on the left to those on the right hand side, Figure 2).
|Figure 2: Fullness and satisfaction after test meals in men (left) and women (right; Zhou. 2014).|
increased fat content by adding oil, sweetness desire was higher in women than in men from 4 h after the meal. The scientists interpret these findings as follows:
In other words: The high fat content annuls the beneficial effect of high vegetable intakes - at least in women. Who tend to have a higher tendency for sweet cravings, anyway - a tendency that was strengthened by high fat intakes and triggered and amplified by reduced rice intake as it was the case in the high meat + low energy diet in the study at hand.
The current study reflects that fat might suppress sweetness desire in a diet with vegetable content as low as 80 g, whereas in a diet with sufficient vegetable content such as 240 g, increased fat content might stimulate the redundant sweetness desire. This stimulation is probably due to initiating a vicious cycle from the increased palatability of the diet. A previous study reported that the increased fat content that promotes the sensory properties of the diet causes insulin/leptin resistance, resulting in more food consumption." (Zhou. 2014)
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