The prevention of obesity and its main medical complications, such as hypertension, type 2 diabetes and cardiovascular diseases, have been become a health priority. One of the most frequent metabolic complications in obesity is the insulin resistance and is the most important risk factor for the development of coronary diseases. The weight loss induced by the restriction of dietary energy is the cornerstone of therapy for people with obesity, as it improves or even regularizes insulin sensitivity and related comorbidities. However, weight loss induced by diet also decreases lean tissue mass, which could result in adverse effects on physical function. Although, regularly recommended to increase protein intake during weight loss, there is evidence to suggest that high protein intake could have deleterious metabolic effects. On the other hand, there is an association between the type of protein consumption, mainly the concentration of branched-chain amino acids (BCAAs) and insulin resistance during the dietary energy restriction in the therapy of obesity. There are multiple factors that influence the concentration of BCAAs and insulin resistance, which can be by phenotypic or genetic modification. The phenotypic modification refers to race, sex and dietary pattern. Meanwhile, the genetic modification refers to the activity of the enzymes responsible for the catabolism of BCAAs and genetic variants, such as the polymorphisms of a single nucleotide of said enzymes. A randomized controlled trial will be conducted with 160 participants (80 women and 80 men) divided by a draw in 4 groups, each for 20 participants. A feeding plan will be assigned according to the distribution of proteins (standard or high) and type of protein (animal or vegetable). The main aim of this study is to evaluate the effect on the amount and type of dietary protein and energy restriction on insulin resistance in subjects with obesity in a period of 1 month, considering the main factors that influence the concentration of BCAAs. In this way, evidence will be provided on what type of dietary intervention is most convenient for weight loss in subjects with insulin resistance and obesity.

STUDY PROGRAM The study will consist of a previous examination and 4 visits during the follow-up period.

Previous visit: pre-admission (Duration approximately 40 minutes)

1. Participants who meet the inclusion criteria will be selected. These will be captured through advertising.
2. Participants will be informed of the characteristics of the study, the risks and the benefits expected after the dietary intervention.
3. Anthropometric and body composition measurements will be made.
4. History of food frequency
5. A blood sample will be taken for the determination of glucose, insulin, total cholesterol, HDL cholesterol, LDL cholesterol, creatinine and urea nitrogen (BUN) in serum.
6. The consent letter will be signed by the participants. Subsequently according to the previous visit if insulin resistance is diagnosed according to the HOMA index (IR-HOMA), The patient will be included in the visit one of the research protocol.

Visit one:

a) Nutritional assessment (Ambulatory Patient Unit)

1. A clinical-nutritional history
2. The determination of anthropometric measurements such as weight, height and waist circumference and body composition by bioimpedance.
3. Resting energy expenditure will be determined by indirect calorimetry
4. A glucose tolerance curve will be performed for 2 hours to determine the area under the insulin and glucose curve and determination of the insulinemic and glycemic indexes.
5. A whole blood sample will be taken for the determination of the serum concentration of glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, c reactive protein (CRP), insulin, leptin, and plasma amino acid profile.
6. A sample will be taken to isolate leukocytes, for the determination of the expression of enzymes related to branched-chain amino acids in leukocytes (BCAT and BCKDH).
7. The physical activity questionnaire will be carried out (IPAQ long version). The patient will be advised not to change the level of habitual physical activity
8. Patients will start consuming the diet corresponding to their group. The different menus will be delivered and explained to the patients.

7. A food guide will be given so that they have food exchange options. 8. You will be taught to fill the feed log. 9. Patients will be cited within a week.

Visit two:

1. A 24-hour dietary record.
2. Food logs will be collected and new ones will be delivered.
3. They will be given and explained the corresponding treatment menus.
4. They will be summoned in a week.

Visit three:

1. A 24-hours dietary record
2. Food logs will be collected and new ones will be delivered.
3. They will be given and explained the corresponding treatment menus.
4. They will be summoned in a week.

Visit four:

a) Nutritional assessment

1. The determination of anthropometric measurements such as weight, waist circumference and body composition measurement will be made by means of bioimpedance.
2. The resting energy expenditure will be determined by indirect calorimetry.
3. A glucose tolerance curve will be carried out for 2 hours to determine the area under the insulin and glucose curve and determination of the insulinemic and glycemic indexes.
4. A whole blood sample will be taken to determine the serum concentration of glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, c-reactive protein (CRP), insulin, leptin, adiponectin and plasma amino acid profile.

6. There will be a 24-hour reminder. 7. The physical activity questionnaire will be carried out (IPAQ long version). The patient will be advised not to change the level of habitual physical activity.

8. Full feed logs will be collected. 9. It will be scheduled within fifteen days for delivery of results. Actions that will be carried out at the end of the study to maintain the continuity of the treatment

All patients after the end of the study, will be cited at 15 days where:

1. You will be given the results

Inclusion Criteria:

• Adults (men and women) between the ages of 18 and 60.
• Patients with obesity (BMI ≥ 30 and ≤ 50 kg / m2) and with insulin resistance (HOMA - IR Index ≥ 2.5).
• Mexican mestizos (parents and grandparents born in Mexico).
• Patients who can read and write.

Exclusion Criteria:

• Patients with any type of diabetes.
• Patients with kidney disease diagnosed by a medical or with creatinine> 1.3 mg / dL for men and > 1.1 mg / dL for women and / or BUN> 20 mg / dL.
• Patients with acquired diseases that produce obesity and diabetes secondarily.
• Patients who have suffered a cardiovascular event.
• Patients with weight loss > 3 kg in the last 3 months.
• Patients with any catabolic diseases.
• Gravidity status
• Positive smoking
• Treatment with any medication

the person who will perform the statistical analysis will be blinded from the intervention group by assigning each patient