You don’t need a new diet. You just need an improved diet. Too often, people who decide to change up their eating habits in search of better fitness make a giant leap from their current habits to some one-size-fits all plan or specialty diet.

Not only are most such diets unnecessarily extreme (you’ll be hard pressed to find an Olympic distance runner who completely avoids entire food groups), but they are also difficult to sustain.

A more humane and effective approach to achieving better fitness is to make specific, targeted changes that are proven to yield results and leave the rest of your preferred eating habits alone. In other words, tweak your routine instead of overhauling it. Here are my top eight recommended dietary tweaks for better fitness.

1. Include at least one vegetable in every meal.

You know you should eat plenty of vegetables. They benefit elite athletes and casual exercisers in ways that range from promoting fat loss to reducing free-radical-induced muscle damage. But good intentions won’t put veggies in your body. Eating three meals a day doesn’t give you many opportunities to meet your ideal vegetable consumption, so take advantage of all of them. It’s not that hard to include at least one veggie in every meal. For example, start your day with a veggie omelet, eat a vegetable-based soup in your midday meal, and have a large salad with your dinner or as your main course. You might not crave vegetables the same way you crave something dripping with cheese or a special sauce, but vegetables—raw or cooked—are chock full of nutrients that help your body recover and thrive.

2. Replace refined grains with whole grains.

Avoiding carbohydrates will not make you fitter. Upgrading your carbohydrate sources will. This is easier than it’s ever been. One way to do this is to replace refined grains (white rice, enriched wheat flour) with whole-grain alternatives (brown rice, 100 percent whole wheat flour). Whole grains are full of vitamins and minerals, like antioxidants and other vitamins in their bran, and B vitamins and healthy fats in their germ. While refined grains like white flour are enriched with nutrients to make up for the ones lost in the processing, many of the nutrients aren’t replaced. Every grain-based food from breakfast cereal to pasta is available in whole-grain forms. Choose them whenever possible, whether you’re cooking your meals or eating out.

3. Eat less red meat and more fish.

Exercise causes inflammation in the muscles and joints—inflammation that your body must combat in order to recover from each workout and be ready for the next. Your diet can either help or hurt this process. Red meat has many benefits, but it tends to promote inflammation, whereas fatty fish (salmon, mackerel, tuna, sardines) is anti-inflammatory. If you’re serious about getting fitter, try to eat these types of fish more often than you eat red meat. Other anti-inflammatory foods to feature regularly in your diet are olive oil, nuts, berries, tomatoes and greens.

4. Avoid added sugars.

Most Americans—including many recreational athletes and avid exercisers—eat too much refined sugar, which promotes weight gain, displaces healthier nutrients from their diet and has other effects that stand in the way of better fitness. Merely avoiding soft drinks and cookies is a good start, but it’s not enough to keep your daily refined sugar intake below the recommended level of 25 grams per day. Sugar is added to all kinds of packaged products where you wouldn’t expect it—bread, pasta sauce, yogurt, salad dressing—and it adds up. Read ingredient labels carefully and choose options that do not contain added sugars.

5. Avoid added oils.

Whereas sugar gets most of the attention, added oils account for more of the extra calories in today’s diet as compared to the diets of past generations. Oils added to snack chips, crackers, packaged baked goods and other products greatly increase both the caloric density and the palatability of foods, so we get more calories per bite and also eat more of them. (And it doesn’t matter whether they’re baked or fried. The effects are the same.) As with refined sugar, read ingredient labels carefully and choose options that do not contain added fats or oils whenever possible.

6. Deconstruct your bars.

Energy bars and snack bars have become extremely popular among fitness seekers, who tend to see them as healthier alternatives to other snacks. While some bars are better than others, even the healthiest products contain high amounts of added sugar and fat alongside good ingredients such as dried fruit and nuts. For a truly healthy snack, “deconstruct” your favorite bar by eating plain dried fruit or nuts instead and leaving behind common ingredients such as agave nectar and safflower oil that add lots of empty calories to bars.

7. Eat more satiating foods.

One of the advantages of natural food types such as fruits and unprocessed meats is that they are more satiating than processed foods like refined grains and fried foods, allowing you to fill up on fewer calories. But even among the natural food types, some specific foods are more satiating than others. Choosing these high-satiety foods regularly will help you get leaner over time. Among the most filling healthy foods are baked and boiled potatoes, bean soups, eggs, apples and oatmeal.

8. Drink fewer calories.

The average American gets 18 percent of his or her daily calories from beverages. Very few of these calories come from healthy sources such as 100 percent vegetable juice that make a valuable contribution to overall nutrition. Reducing beverage calories is therefore one of the simplest and most effective ways to achieve a leaner body composition. Replace high-calorie caffeinated drinks with lightly sweetened or unsweetened coffee or tea, substitute soft drinks with water, and limit yourself to one serving of alcohol per day or less.