the science of weight loss

If your health and fitness goal includes weight loss, you have probably heard, read or watched a lot of different opinions on what is the best way to achieve it. You have probably also struggled with knowing what information is reliable versus what is not. In order to see what the scientific community had to say on the topic I read some research reviews to determine what was the most effective way of losing weight.
 
Diet
The simplest answer is to create a caloric deficit by eating less. The most effective way of achieving this end is to eat a diet higher in protein. For a long time you have probably heard that high protein diets (think Paleo and Atkins) are effective for weight loss, and they are. Changing your diet around to include higher protein seems to be the most effective way to lose weight, but maintain muscle. You can also opt for meal replacement shakes to get your protein and vitamins in, but in a calorie restricted way. The last trick is to go to bed hungry if your goal is weight loss. A quick word of caution on low carb diets: initially restricting them can lead to weight loss, but long term restriction can lead to sensitivity and weight rebounding. After an initial decrease add some more complex carbs in (rice, sweet potatoe, bread, etc), but focus it in the morning and after a hard workout.
 
Exercise
For a while the recommendation has been to focus on diet and do cardiovascular exercise in order to lose weight. While steady state exercise has its place, it is not the most effective way to lose weight. Once you start moving and get used to a routine, weight training is the most important for weight loss. And, not just any weight training, but heavier lifting with lower reps seems to build muscle and decrease fat mass. Doing whole body exercises 3 times a week for 2-3 sets of 6-10 repetitions is the scientific recommendation if the goal is weight reduction. Ironically, this is the same recommendation if the goal is strength development, as well. For the non-endurance athletes, choosing endurance exercises that incorporate circuit training or interval training is also effective to achieve weight reduction. Just make sure that you are working at a high intensity,  the best results in the studies were obtained when exercise was performed this way.
 
Lifestyle
If diet is effective alone and exercise is effective alone, then what about the combination of diet and exercise on weight reduction. This in fact, is the most effective way to reduce weight. By adopting a calorie restricted diet and increasing your strength or interval training exercise you will have the optimal scientific plan for weight reduction.  For people that have achieved 10% weight loss and have managed to sustain that reduction, it was discovered that they ate a diet fewer in calories than other groups who could not sustain weight loss and that the diet was higher in protein and lower in fat. They also moved more throughout the day than their counterparts. Using a fitness app to track your calories and steps is an easy to see how active you are. Simply increasing the number of steps and stairs throughout the day will have a positive effect on your goal.
 
Conclusion
In order to lose weight and maintain that loss it is important to adopt a lifestyle that supports that goal.

• Eat a calorie restricted diet that is high in protein and low in fat
• Move more throughout the day. This increase in baseline activity is helpful.
• Exercise at the right intensity. Strength train 3 times a week doing whole body exercises for 2-3 sets of 6-10 repetitions
• Do higher intensity interval training or circuit training workouts 1-3x a week at an intensity above 70% of your max. If you use a machine, choose the interval workout or spend more time jogging or hiking hills and climbing stairs.
  

Following these recommendations should help you achieve your goal. Good luck!
 
References
American Dietetic Association. (2009). Position of the American Dietetic Association: Weight Management. Journal of the American Dietetic Association; February 2009 (109): 2
Clark, J. (2015). Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight loss and changes in fitness for adults (18-65) who are overfat, or obese; systematic review and meta analysis. Journal of Diabetes and Metabolic Disorders (14): 31
Turocy, et. al. (2011). National Athletic Trainer’s Association Position Statement: Safe weight loss and maintenance practices in sport and exercise. Journal Athletic Training (46): 3
Wilson, P. (2016). Physical activity and dietary determinants of weight loss success in the general US  population. American Journal of Public Health (106): 2