no smoke and mirrors

Reader's Digest １月号の記事 "Secrets of the slim" に出てきた表現です。
There aren't any magic weight-loss foods (sorry, grapefruit!) but there are specific dietary habits - we call them "diet do's" - that work for most people. Some of them might not come naturally at first (like eating breakfast) and others may require a bit more effort (keeping a food diary), but stick with them for real results (no smoke and mirrors, promise!)
最後の括弧書きにある慣用句らしい "no smoke and mirrors" がよく分かりませんので辞書を見ます。 "smoke and mirrors" で次の説明がありました。
・Oxford English Dictionary: The obscuring or embellishing of the truth of a situation with misleading or irrelevant information: the budget process is an exercise in smoke and mirrors
・Cambridge English Dictionary: Something that is described as smoke and mirrors is intended to make you believe that something is being done or is true, when it is not: The new budget isn't smoke and mirrors; it's an honest attempt to reduce the deficit.