Stephan Guyenet discusses a study titled “A Satiety Index of Common Foods” by Dr. SHA Holt and colleagues.
This study, along with many others, suggests that focusing on simple foods that have a lower energy density leads to greater fullness and less subsequent food intake, and conversely that highly palatable energy-dense foods promote excessive food intake. Potatoes, sweet potatoes, meats, fish, vegetables, fruits, rice and beans are foods with a moderate level of palatability and energy density, and are consequently helpful for weight loss and maintenance. Conversely, baked goods, candy, ice cream and fried foods have the lowest SI, reflecting their extreme palatability and energy density. These are exactly the same foods people eat to relieve stress, which reinforces the fact that they are hyper-palatable and hyper-rewarding. In my opinion, these are among the most fattening foods, and the obesity literature as a whole supports this.
Read Stephan’s full post here.
I wouldn’t be surprised if this relationship was in some way an effect of missed dopamine predictions. I am currently reading How We Decide by Jonah Lehrer. He discusses how, after successfully learning an action to gain a reward, our brain releases dopamine in anticipation of the reward when we repeat that action. This means our brain learns patterns and reacts in expectation of those patterns. But, if that action response changes and no longer provides the same reward, our brain changes to no longer release dopamine. So if you are throwing back peanut-butter cups, each time anticipating that super-sweet reward, your brain releases dopamine as soon as you reach for the next bite, before you even open the wrapper. What would happen if you unwittingly grabbed a chunk of sweet potato that felt exactly like the candy? Total let-down on taste resulting in a reduced dopamine response. It’s a stretch, but I’ll bet you could break the streak of over-eating.
A very informative post by Stephan Guyenet on the different types of sugar and how our bodies react to them.
Here are the take-home points from this post:
- Sugar, including fructose, is not inherently fattening relative to other calorie sources, and unrefined sugar is compatible with fat loss in the context of simple whole food diets.
- Sugar can be fattening in certain contexts, specifically if it is added to foods and beverages to increase their palatability, reward value and energy density.
- Sugar-sweetened beverages are probably one of the most fattening elements of the modern diet.
- Fruit is not fattening, and it may actually be slimming.
- In excess, refined sugar can cause body fat to redistribute from the subcutaneous depot (under the skin, where you want it) to the visceral depots and the liver (where you don’t want it). It can also cause insulin resistance in the liver and increase blood pressure, all components of the ‘metabolic syndrome’. This is caused specifically by the fructose portion of the sugar.
Here are the implications:
- Avoiding sugar-sweetened foods, and particularly sugar-sweetened beverages (soda, punch, sweetened coffee, cocktails, maybe fruit juice as well?) can prevent and to some extent reverse fat gain and metabolic dysfunction.
- I see no reason to believe that refined and unrefined sugars, used in the same context (e.g. muffins baked with white vs. brown sugar), would have different effects on body fatness. However, unrefined sugars may be less harmful to other aspects of health, because they contain other substances that may be protective. Mark Sisson discussed this idea in a recent post on honey (38).
- Eating fruit does not contribute to fat gain in most people, but instead probably favors leanness. Fruit is a whole food with a low energy density and a moderate palatability and reward value.
Get the full story on his blog.
Study comparing short-term effects of sucrose and HFCS.
Both HFCS and sucrose have historically been considered to have nearly identical effects on the body. But this study finds that indeed there is a difference between the two. They found that the makeup of the sugars resulted in differences in how much fructose was absorbed into the circulation, and which could have potential impact on one’s health. Sucrose is 50 percent fructose and 50 percent glucose that is bonded together as a disaccharide (complex carbohydrate) and HFCS is a mixture of free fructose (55%) and free glucose (45%). It’s the difference in fructose amount that appears to create the ill health effects on the body.
Their study was conducted at the University of Florida, where they evaluated 40 men and women who were given 24 ounces of HFCS- or sugar-sweetened soft drinks. Careful measurements showed that the HFCS sweetened soft drinks resulted in significantly higher fructose levels than the sugar-sweetened drinks. Fructose is also known to increase uric acid levels that have been implicated in blood pressure, and the HFCS-sweetened drinks also resulted in a higher uric acid level and a 3 mm Hg greater rise in systolic blood pressure.
Summarized on Medical News Today.
Study full text here.
via Martin Berkhan.