Topic sentences indicate what each paragraph in your paper is about. Think of the topic sentence as a headline for the paragraph. Topic sentences help you to:
- Identify the focus of the paragraph.
- Show how the paragraph supports the overall thesis statement.
- Make transitions between paragraphs (for example, by expanding on a point or making a comparison).
How to write topic sentences
Topic sentences aren’t the first or the last thing you write – you’ll develop them throughout the writing process. The first step is to make sure you have a strong thesis statement. The thesis statement sums up the purpose and argument of the whole paper.
Thesis statement example
Food is an increasingly urgent environmental issue, and to reduce humans’ impact on the planet, it is necessary to change global patterns of food production and consumption.
Next, you should make an outline of your essay structure, planning what you want to say in each paragraph and what evidence you’ll use.
Then, as you write, you can start each paragraph with a topic sentence. This sentence should introduce the central point of the paragraph and show how it supports or develops the thesis statement.
Topic sentence example
Research has consistently shown that the meat industry has a significant environmental impact.
The rest of the paragraph’s evidence and arguments should flow logically from this sentence.
Topic sentences as transitions between paragraphs
The topic sentence doesn’t always have to be a simple statement. To make your writing stronger, you can use topic sentences to create smooth transitions between paragraphs. Ask yourself: how does this point relate to what you wrote in the preceding paragraph? Depending on the answer, your topic sentence might do any of the following things.
Emphasize and expand
If this paragraph goes into more detail or adds more evidence to make the same point, the topic sentence can use words that imply emphasis or similarity (for example, furthermore, indeed, in fact, also).
Indeed, cattle farming alone is responsible for a large proportion of greenhouse gas emissions, and has serious impacts in terms of water and land use.
Summarize and anticipate
If the paragraph turns to a different aspect of the same subject, the topic sentence can briefly sum up the previous paragraph and anticipate the new information that will appear in this one.
While beef clearly has the most dramatic environmental impact, other animal products also contribute significantly to global emissions.
Compare and contrast
If the paragraph makes a comparison or introduces contrasting information, the topic sentence can use words that highlight difference or conflict (for example, in contrast, however, yet, on the other hand).
However, the environmental costs of dietary choices are not always clear-cut; in some cases, small-scale livestock farming could be more sustainable than certain forms of plant-based food production.
You can also imply contrast or complicate your argument by formulating the topic sentence as a question.
Is veganism the only solution, or are there more sustainable ways of producing meat and dairy?
Topic sentences that introduce more than one paragraph
Sometimes you can use a topic sentence to introduce several paragraphs at once. All of the examples above address the environmental impact of meat-eating versus veganism. Together, they make up one coherent part of a larger argument, so the first paragraph could use a topic sentence to introduce the whole section.
In countries with high levels of meat consumption, a move towards plant-based diets is the most obvious route to making food more sustainable.Research has consistently shown that the meat industry has significant environmental impacts.
Where does the topic sentence go?
The topic sentence usually goes at the very start of a paragraph, but sometimes it can come later to indicate a change of direction in the paragraph’s argument.
Given this evidence of the meat industry’s impact on the planet, veganism seems like the only environmentally responsible option for consumers. However, the environmental costs of dietary choices are not always clear-cut; in some cases, small-scale livestock farming could be more sustainable than certain forms of plant-based food production.
In this example, the first sentence summarizes the main point that has been made so far. Then the topic sentence indicates that this paragraph will address evidence that complicates or contradicts that point.
In more advanced or creative forms of academic writing, you can play with the placement of topic sentences to build suspense and give your arguments more force. But if in doubt, to keep your paper clear and focused, the easiest method is to place the topic sentence at the start of the paragraph.
Ready to start writing or need guidance on another part of the writing process? Read our easy guide on how to write a research paper.