This is an excerpt from Your Workout PERFECTED by Nick Tumminello.
We can't talk about fat loss without talking about eating behaviors (a.k.a. diet). You won't find a more common question than, How should I eat for fat loss? For an answer you'll get lots of different opinions. The fact is, this issue, along with other issues like it, isn't about what this or that so-called expert says, and it's definitely not about what some athlete, trainer, or lean person at gym says. It's about what the body of scientific evidence - not just a single study - says when taken as a whole.
The International Society of Sports Nutrition (ISSN) has provided a list of conclusions and recommendations (for eating and exercising) in their position stand paper on diets and body composition. Here are a few of major takeaways from the ISSN's scientific paper:
- There are many diet types and eating styles. The various diet archetypes are wide-ranging in total energy and macronutrient distribution. Each type carries varying degrees of supporting data and unfounded claims.
- A wide range of dietary approaches (low-fat to low-carbohydrate/ketogenic, and all points between) can be similarly effective for improving body composition, and this allows flexibility with program design. To date, no controlled, inpatient isocaloric (i.e., calories matched) diet comparison, where protein is matched between groups, has reported a clinically meaningful fat loss or thermic (i.e., metabolic) advantage to the lower-carbohydrate or ketogenic diet.
- Common threads run through the diets in terms of the mechanism of action for weight loss and weight gain (i.e., sustained hypocaloric versus hypercaloric conditions), but there are also potentially unique means by which certain diets achieve their intended objectives (e.g., factors that facilitate greater satiety, ease of compliance, support of training demands).
- Diets focused primarily on fat loss (and weight loss beyond initial reductions in body water) operate under the fundamental mechanism of a sustained caloric deficit. This net hypocaloric (i.e., reduced calorie) balance can either be imposed daily or over the course of the week.
- The collective body of research about intermittent caloric restriction (i.e., intermittent fasting) demonstrates no significant advantage over daily caloric restriction for improving body composition. Increasing dietary protein to levels significantly beyond current recommendations for athletic populations may improve body composition. The ISSN's original 2007 position on protein intake (1.4-2.0 g/kg) has gained further support from subsequent investigations arriving at similar requirements in athletic populations. Higher protein intakes (2.3-3.1 g/kg Fat Free Mass) may be required to maximize muscle retention in lean, resistance-trained subjects in hypocaloric conditions. Emerging research on very high protein intakes (>3 g/kg) has demonstrated that the known thermic, satiating, and lean mass-preserving effects of dietary protein might be amplified in resistance training subjects.
- Most existing research showing adaptive thermogenesis (i.e.,a slowing of metabolism) has involved diets that combine aggressive caloric restriction with low protein intakes and an absence of resistance training, essentially creating a perfect storm for slowing metabolism. Research that has mindfully included resistance training and adequate protein has circumvented the problem of adaptive thermogenesis and muscle loss, despite very low-calorie intakes.
- The long-term success of a diet depends on compliance.
As you can see, the relationship of how many calories you consume per day to the number you expend per day is the single most important factor when it comes to determining whether you lose fat.
Now, whenever someone says this, someone else tries to refute it by bringing up the fact that the quality or composition of the calories you eat matters. They present it as an either/or proposition. But this relationship doesn't discount that some calories are more nutrient dense than others. (After all, we've all heard the term "empty calories.") It simply demonstrates that one can be both well nourished and overfed. Food quality and food quantity are important factors that should be considered together; as important as it is to eat high-quality, nutrient-dense foods for general health, you can still gain fat from eating "healthy" if you eat too many calories relative to what you're expending.
That said, focus on the quality of the foods you eat. Emphasize fruits and vegetables and high-quality meats, eggs, and fish (or protein substitutes, for vegetarians and vegans), while limiting refined foods, simple sugars, hydrogenated oil, and alcohol. Fruits, veggies, and lean proteins are generally lower in calories than things like fast food and candy. Don't overeat. Stop before you feel bloated and stuffed. You'll likely end up taking in fewer calories without even actually counting them.
You don't just want to be well fed; you want to be well nourished. Emphasizing the quality (i.e., nutrient density) of the foods you eat over the quantity (i.e., number of calories) is an easy approach. Try it and see where that gets you. It spells success for most people.
But it's certainly possible to eat too many calories from nutrient-dense, high-quality foods. Don't think for a second that you can't gain fat from eating "healthy." While you can first emphasize the quality of the foods you eat and see where that strategy gets you, it may only take you so far. You may need another strategy as well. The next step is to focus on the caloric quantity of the food you're eating and put yourself into a caloric deficit. The ways to create a caloric deficit involve eating fewer calories, increasing your activity level to expend more calories, or a combination of both.