Health topics in seven minutes should only have one (maybe two elements) and should address only a small portion of a larger topic. Though the benefit of eating healthy is always timely, it is also too large a topic. Focusing on smaller topics within health can help the speaker accomplish his goals. Why blueberries benefit the digestive system, how lycopene in tomatoes helps fight prostate cancer and why milk helps bone development are topics a speaker can address in a short amount of time. Make sure speeches on this subject do not contain "doctor-speak," meaning complicated medical terms or procedures and terminology that take a long time to explain or that people simply don't understand.
Technology topics make great "how to" demonstrations for an audience about the latest gadget to hit the market. Showing people how something works, its benefits, its downfalls and how best to use it grabs attention. Speakers should practice several times before giving a speech like this before a group of people. Most important, make sure the product works and know how to work it (even things not used in the demonstration in case people ask questions). A more informative or persuasive topic can work as an alternative about using technology in a particular class project (or other educational setting) or how social media can expand a business or nonprofit organization.
Social issues affect just about every community regardless of economic status. The war on drugs, homelessness, poverty and bullying affect schools, governments and police departments. Accompanying a speech on social issues with a good story would engage the audience and perhaps persuade listeners to take action about something. Telling a personal story about overcoming a drug problem, describing the benefits to society of teaching someone at a homeless shelter how to read, discussing donations to a food pantry or encouraging students not to bully a child with special needs might inspire someone to change his mind or behavior.
A seven-minute topic on the economy can range from how to invest money to how to save money at the grocery store. "The Impact of Fast Food Restaurants on the U.S. Economy" makes an interesting book topic, but addressing all of the talking points in seven minutes presents a challenge. Narrowing the topic by cuisine, section of the country or even ownership helps the speaker focus and create a more manageable presentation.