Day7 People who use the artificial sweetener aspartame are better off consuming sugar

The following appeared in the health section of a magazine on trends and lifestyles：

“People who use the artificial sweetener aspartame are better off consuming sugar，since aspartame can actually contribute to weight gain rather than weight loss.For example，high levels of aspartame have been shown to trigger a craving for food by depleting the brain of a chemical that registers satiety，or the sense of being full.Furthermore，studies suggest that sugars，if consumed after at least 45 minutes of continuous exercise，actually enhance the body’s ability to burn fat.Consequently，those who drink aspartame-sweetened juices after exercise will also lose this calorie-burning bene？t.Thus it appears that people consuming aspartame rather than sugar are unlikely to achieve their dietary goals.”

Discuss how well reasoned you find this argument.In your discussion be sure to analyze the line of reasoning and the use of evidence in the argument.For example，you may need to consider what questionable assumptions underlie the thinking and what alternative explanations or counterexamples might weaken the conclusion.You can also discuss what sort of evidence would strengthen or refute the argument，what changes in the argument would make it more logically sound，and what，if anything，would help you better evaluate its conclusion.

文勇五问：

（1）本段的事实是什么？结论是什么？“For example，high levels of aspartame have been shown to trigger a craving for food by depleting the brain of a chemical that registers satiety，or the sense of being full.Furthermore，studies suggest that sugars，if consumed after at least 45 minutes of continuous exercise，actually enhance the body’s ability to burn fat.”是事实，“Thus it appears that people consuming aspartame rather than sugar are unlikely to achieve their dietary goals.”是结论，值得反驳吗？

（2）可以简单地用高浓度的aspartame所造成的情形作为例子来判断所有情况下aspartame是否有利吗？是否有以一概全的风险？低浓度时的情况如何呢？

（3）糖分所拥有的特点，是在特殊情况下实现的，也就是在“连续45分钟以上的运动后”。那么，时间低于45分钟的情况是怎样的呢？

（4）糖分有没有可能像aspartame一样，也会“trigger a craving for food by depleting the brain of a chemical that registers satiety”？aspartame有没有可能像糖分一样，也会“enhance the body’s ability to burn fat”？原文有给出足够的信息吗？

（5）文中只给出了饱腹感和机体消耗脂肪效率这两个方面的信息，这包括了某类食物在减肥方面能起到作用的所有决定要素吗？你能罗列一两个其他可能的要素吗？例如：食物摄入体内后转换为脂肪的比率；其他日常饮食起作用后的减肥效果。

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